Method for processing substrate and substrate processing apparatus

ABSTRACT

There is provided a substrate processing method, comprising the steps of: supplying source gas into a processing chamber in which substrates are accommodated; removing the source gas and an intermediate body of the source gas remained in the processing chamber; supplying ozone into the processing chamber in a state of substantially stopping exhaust of an atmosphere in the processing chamber; and removing the ozone and the intermediate body of the ozone remained in the processing chamber; with these steps repeated multiple number of times, to thereby form an oxide film on the surface of the substrates by supplying the source gas and the ozone alternately so as not to be mixed with each other.

This application is a divisional of application Ser. No. 13/313,736filed Dec. 7, 2011, which in turn is a divisional of application Ser.No. 12/457,779 filed Jun. 22, 2009, now abandoned. The entiredisclosures of the prior applications are hereby incorporated byreference herein.

BACKGROUND

Technical Field

The present invention relates to a substrate processing method and asubstrate processing apparatus.

Description of Related Art

As one of the manufacturing steps of a semiconductor device such as IC,a substrate processing step using an ALD (Atomic Layer Deposition)method and a CVD (Chemical Vapor Deposition) method is performed. Avertical substrate processing apparatus is used as a substrateprocessing apparatus for performing the substrate processing step. Thevertical substrate processing apparatus includes a reaction tube forforming a processing chamber; a gas supply unit for supplying processinggas into the processing chamber; an exhaust unit for exhausting insideof the processing chamber; and a heater unit for heating the inside ofthe processing chamber. The vertical substrate processing apparatus iscapable of processing a plurality of substrates by a single batchprocessing, and therefore has a characteristic that throughput(productivity) is higher than a sheet-type substrate processingapparatus.

FIG. 20 is a schematic view showing a structure of a processing furnaceof a conventional vertical substrate processing apparatus. Thisprocessing furnace includes a reaction tube 203′ made of, for example,quartz (SiO₂). A processing chamber 201′ is formed in the reaction tube203′. Boats (not shown) as substrate holding tools for supporting aplurality of wafers as substrates, are loaded into the processingchamber 201′ in multiple stages. The processing furnace includes a gassupply unit for supplying processing gas such as source gas and oxidegas into the processing chamber 201′. The gas supply unit includes afirst gas supply tube 232 a′ for supplying the source gas (such as a gascontaining element Zr); a second gas supply tube 232 b′ for supplyingthe oxide gas (such as an ozone (O₃) gas); a first gas supply nozzle 233a′ connected to the first gas supply tube 232 a′; and a second gassupply nozzle 233 b′ connected to the second gas supply tube 232 b′. Thefirst gas supply nozzle 233 a′ and the second gas supply nozzle 233 b′are respectively provided in the reaction tube 203′, so as to bevertically extended from a lower part of the reaction tube 203′ to aceiling part of the reaction tube 203′ along an inner wall of thereaction tube 203′. A plurality of gas jet holes are respectivelyprovided in the first gas supply nozzle 233 a′ and the second gas supplynozzle 233 b′. An arrangement pitch of the gas jet holes is made to besame as a support pitch of the plurality of wafers (not shown) supportedby the aforementioned boats (not shown) in multiple stages. The gas jetholes are constituted so that the processing gas can be flown along anupper surface of each wafer. The first gas supply tube 232 a′ isconnected to a source gas supply source for supplying source gas,through a valve 243 a′. The second gas supply tube 232 b′ is connectedto an oxide gas supply source for supplying oxide gas through a valveAV2′. Note that although not shown, the processing furnace furtherincludes a carrier gas line for supplying N₂ gas, being a carrier gas(purge gas), into the processing chamber 201′, and an exhaust unit forexhausting an atmosphere in the processing chamber 201′.

For example, in the substrate processing step using the ALD method,first source gas supplying step→N₂ purging step→first exhaustingstep→second source supplying step→N₂ purging step→second exhausting stepare set as one cycle, and this cycle is repeated multiple number oftimes. In the first source gas supplying step, the valve AV2′ is closedand the valve 243 a′ is opened, while exhausting the inside of theprocessing chamber 201′ by the exhaust unit (not shown), and the sourcegas is supplied into the processing chamber 201′. Thus, the source gasjetted from each gas jet hole of the first gas supply nozzle 233 a′ isflown horizontally on each wafer, then is adsorbed on the surface of thewafer, to thereby form a base film on the wafer. In the N₂ purging step,the valve AV2′ and the valve 243 a′ are closed while continuing exhaustof the inside of the processing chamber 201′ by the exhaust unit (notshown), and N₂ gas, being purge gas, is supplied into the processingchamber 201′ from a carrier gas line (not shown). Thus, the source gasremained in the processing chamber 201′ is discharged from theprocessing chamber 201′, and the inside of the processing chamber 201′is purged. In the first exhausting step, supply of the N₂ gas from thecarrier gas line (not shown) is stopped, with the valve AV2′ and thevalve 243 a′ closed, while continuing the exhaust of the inside of theprocessing chamber 201′ by the exhaust unit (not shown). Thus, theinside of the processing chamber 201′ is exhausted and cleaned. In theoxide gas supplying step, O₃ gas, being the oxide gas, is supplied intothe processing chamber 201′, with the valve 243 a′ closed and the valveAV2′ opened, while continuing the exhaust of the inside of theprocessing chamber 201′. Thus, the oxide gas jetted from each gas jethole of the second gas supply nozzle 233 b′ is flown horizontally oneach wafer, which is then reacted with the base film formed on thewafer, to thereby form an oxide film on the wafer.

Thus, in the ALD method and the CVD method, oxide gas containing, forexample, ozone, being oxide species, is used as a second source, so thatozone is horizontally supplied along an upper surface of each wafer.However, if processing is performed by a conventional vertical substrateprocessing apparatus, there is a tendency that oxidation is easilyadvanced on an outer peripheral side of the wafer to which ozone issupplied easily, and oxidation is delayed on a center side of the waferto which ozone is hardly supplied. Therefore, a film thicknessdistribution and composition distribution in a surface of the wafer aredeteriorated, thus generating variation in the characteristic of thesemiconductor device, and a manufacturing yield of the semiconductordevice is deteriorated in some cases.

Therefore, the following two methods have been examined. One of them isa method of preventing a delay in oxidation in the center part of thewafer, by increasing a flow speed of the oxide gas containing ozone onthe wafer. The other one is a method of processing substrates uniformlyin the surface, by eliminating an uneven oxidation over the whole wafer,by supplying to the wafer, a large flow rate of the oxide gas containinghigh density ozone.

However, in the former method, sufficient improvement is not observed,and it is difficult to sufficiently prevent the delay in oxidation inthe center part of the wafer, and it is difficult to improve themanufacturing yield of the semiconductor device.

Further, in the latter method, the yield can be improved. However, aflow rate of high density ozone that can be supplied at once is reduced,in terms of a performance of ozonizer (not shown) of the oxide gassupply source, then supply time of ozone is prolonged, and throughput(productivity) is deteriorated.

An object of the present invention is to shorten a processing time andimprove uniformity of a film thickness in the surface, when the oxidefilm is formed by supplying the oxide gas onto the substrate.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, there is provideda substrate processing method, including the steps of:

supplying source gas into a processing chamber in which substrates areaccommodated;

removing the source gas and an intermediate body of the source gasremained in the processing chamber;

supplying ozone into the processing chamber, in a state of substantiallystopping an atmosphere in the processing chamber;

removing the ozone and the intermediate body of the ozone remained inthe processing chamber,

with these steps repeated multiple number of times, and the source gasand the ozone alternately supplied so as not to be mixed with eachother, to thereby form an oxide film on the surface of the substrates.

According to other aspect of the present invention, there is provided asubstrate processing method, including the steps of:

supplying source gas into a processing chamber in which substrates areaccommodated;

exhausting an atmosphere in the processing chamber;

reserving the ozone into a gas reservoir connected to the processingchamber;

supplying into the processing chamber the ozone reserved into the gasreservoir; and

exhausting the atmosphere in the processing chamber,

with these steps repeated multiple number of times, and the source gasand the ozone alternately supplied so as not to be mixed with eachother, to thereby form an oxide film on the surface of the substrates.

According to further another aspect of the present invention, there isprovided a substrate processing method, including the steps of:

loading substrates into a processing chamber;

supplying ozone into the processing chamber, in a state of substantiallystopping exhaust of an atmosphere in the processing chamber; and

removing the ozone and an intermediate body of the ozone remained in theprocessing chamber,

with the step of supplying ozone and the step of removing the ozonerepeated multiple number of times, to thereby form an oxide film on thesurface of the substrates.

According to further another aspect of the present invention, there isprovided a substrate processing method, including the steps of:

reserving ozone into a gas reservoir connected to a processing chamberin which substrates are accommodated;

supplying into the processing chamber the ozone reserved into the gasreservoir; and

exhausting an atmosphere in the processing chamber,

with these steps repeated multiple number of times, to thereby form anoxide film on the surface of the substrates.

According to further another aspect of the present invention, there isprovided a substrate processing apparatus, including:

a processing chamber that processes substrates;

a gas supply unit that supplies ozone into the processing chamber;

an exhaust unit that exhausts an atmosphere in the processing chamber;and

a controller,

with the gas supply unit including an ozone supply path connected to theprocessing chamber, and an ozone supply valve that performs open/closeof the ozone supply path,

the exhaust unit including an exhaust path connected to the processingchamber, and an exhaust valve for opening and closing the exhaust path,

the controller controlling the gas supply unit and the exhaust unit, sothat the ozone is supplied into the processing chamber from the ozonesupply path, in a state of substantially stopping an exhaust of insideof the processing chamber, when the ozone is supplied into theprocessing chamber.

According to the present invention, when the oxide film is formed bysupplying the oxide gas onto the substrates, it is possible to shorten aprocessing time and improve uniformity of the film thickness in thesurface.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram showing an entire structure of asubstrate processing apparatus according to a first embodiment of thepresent invention.

FIG. 2 is a vertical sectional view of a processing furnace of thesubstrate processing apparatus according to the first embodiment of thepresent invention.

FIG. 3 is a horizontal sectional view corresponding to a sectional facetaken along the line A-A of the processing furnace shown in FIG. 2.

FIG. 4 is a schematic block diagram of the processing furnace and a gassupply unit of the substrate processing apparatus according to a thirdembodiment of the present invention.

FIG. 5 is a sequence view of the step of forming an oxide film accordingto a comparative example.

FIG. 6 is a schematic view showing a sequence example 1 of the step offorming the oxide film (step 3) according to a third embodiment of thepresent invention.

FIG. 7 is a schematic view showing a sequence example 2 of the step offorming the oxide film (step 3) according to the third embodiment of thepresent invention.

FIG. 8 is a schematic view showing a sequence example 3 of the step offorming the oxide film (step 3) according to the third embodiment of thepresent invention.

FIG. 9 is a table chart explaining examples 1 to 3 of the presentinvention together with a comparative example 1, showing an averageoxide film thickness, a substrate center film thickness, and uniformityof film thickness.

FIG. 10 is a graph chart explaining examples 4 to 6 of the presentinvention together with a comparative example 2, FIG. 10A shows arelation between an increase of an average film thickness and oxidationtime of the oxide film in a substrate surface, and FIG. 10B shows arelation between the increase of the film thickness and the oxidationtime of the oxide film in a center part of the substrate, respectively.

FIG. 11 is a table chart for explaining examples 7 and 8 of the presentinvention together with comparative example 3, showing the averagethickness and uniformity of the thickness of the oxide film in each caseof an upper part and a lower part of a substrate processing position.

FIG. 12 is a table chart showing a composition uniformity of a HfO₂ filmin each part of an upper part, a middle part, and a lower part of thesubstrate processing position, wherein FIG. 12A shows the compositionuniformity of comparative example 4 and FIG. 12B shows the compositionuniformity of example 9, and FIG. 12C shows the composition uniformityof example 10, respectively.

FIG. 13 is a schematic block diagram of a processing furnace and a gassupply unit of the substrate processing apparatus according to a fourthembodiment of the present invention.

FIG. 14 is a view exemplifying an operation of the gas supply unit and avalve open/close sequence according to the fourth embodiment of thepresent invention.

FIG. 15 is a view exemplifying a cooling structure of a buffer tankaccording to the third embodiment of the present invention.

FIG. 16 is a view exemplifying other cooling structure of the buffertank according to the third embodiment of the present invention.

FIG. 17 is a schematic block diagram when the gas supply unit accordingto the third embodiment is applied to a side flow-type verticalsubstrate processing apparatus.

FIG. 18 is a vertical sectional view of a processing furnace of the sideflow type vertical substrate processing apparatus according to a secondembodiment of the present invention.

FIG. 19 is a perspective view showing a modified example of an innertube of the substrate processing apparatus according to the secondembodiment of the present invention.

FIG. 20 is a schematic block diagram of a conventional verticalsubstrate processing apparatus.

DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTION First Embodiment

First, a basic structure of a normal flow type vertical substrateprocessing apparatus according to a first embodiment of the presentinvention, and a substrate processing method executed by this substrateprocessing apparatus will be described.

(1) Structure of a Substrate Processing Apparatus

FIG. 1 is a schematic block diagram showing an entire structure of asubstrate processing apparatus according to this embodiment. As shown inthe figure, a substrate processing apparatus 101 includes a casing 111.In order to carry a wafer (substrate) 200 made of silicon, etc, into/outof the casing 111, a cassette 110, being a wafer carrier accommodatingthe wafer (substrate) 200 made of silicon, etc, is used. A front sidemaintenance port (not shown) is opened, as an opening part opened in alower part of a front side wall 111 a of the casing 111 of the substrateprocessing apparatus 101, so that maintenance of an inside of the casing111 can be performed. A front side maintenance door (not shown) foropening/closing this front side maintenance port is built on the frontside wall 111 a of the casing 111. A cassette loading/unloading port(substrate container loading/unloading port) 112 is opened on themaintenance door, so as to communicate inside and outside of the casing111. The cassette loading/unloading port 112 is opened and closed by afront shutter (open/close mechanism of the substrate containerloading/unloading port) 113. A cassette stage (substrate containertransferring stand) 114 is installed inside of the casing 111 of thecassette loading/unloading port 112. The cassette 110 is loaded on thecassette stage 114, and unloaded from the cassette stage 114, by anin-step carrying device (not shown).

The cassette 110 is placed on the cassette stage 114, so that the wafer200 in the cassette 110 takes a vertical posture, and a wafercharging/discharging port of the cassette 110 is faced upward. Thecassette 114 is constituted, so that the cassette 110 is verticallyrotated by 90 degrees toward a rear of the casing 111, with the wafer200 set in a horizontal posture in the cassette 110, and the wafercharging/discharging port of the cassette 110 is faced rearward in thecasing 111.

A cassette shelf (substrate container placement shelf) 105 is set inapproximately a longitudinally center part in the casing 111. Thecassette shelf 105 is constituted, so that a plurality of cassettes 110are stored in multiple stages and in multiple rows. A transfer shelf 123is provided on the cassette shelf 105, on which the cassette 110, beinga carrying object of a wafer transfer mechanism 125 as will be describedlater, is stored. Further, a spare cassette shelf 107 is provided in anupper part of the cassette stage 114, for storing the cassette 110 asspare.

A cassette carrying device (substrate container carrying device) 118 isinstalled between the cassette stage 114 and the cassette shelf 105. Thecassette carrying device 118 includes a cassette elevator (substratecontainer elevation mechanism) 118 a capable of elevating the cassette110 in a state of holding the cassette 110, and a cassette carryingmechanism (substrate container carrying mechanism) 118 b, being acarrying mechanism capable of horizontally moving the cassette 110 in astate of holding the cassette 110. By continuous motion of thesecassette elevator 118 a and cassette carrying mechanism 118 b, thecassette 110 is carried among the cassette stage 114, the cassette shelf105, and the spare cassette shelf 107.

The wafer transfer mechanism (substrate transfer mechanism) 125 is setin the rear of the cassette shelf 105. The wafer transfer mechanism 125includes a wafer transfer device (substrate transfer device) capable ofhorizontally rotating or linearly moving the wafer 200, and a wafertransfer device elevator (substrate transfer device elevation mechanism)125 b for elevating the wafer transfer device 125 a. Note that the wafertransfer device 125 a includes a tweezer (jig for transferringsubstrates) 125 c for holding the wafer 200 in a horizontal posture. Thewafer transfer device elevator 125 b is installed on a right side endportion of the casing 111 having pressure resistance. By the continuousmotion of these wafer transfer device 125 a and wafer transfer deviceelevator 125 b, the wafer 200 is picked up from the inside of thecassette 110 on the transfer shelf 123 and charged into a boat(substrate supporting member) 217 as will be described later anddischarged form the boat 217, and stored in the cassette 110 on thetransfer shelf 123.

A processing furnace 202 is provided in a rear upper part of the casing111. An opening (furnace port) is formed in a lower end portion of theprocessing furnace 202. This opening is opened/closed by a furnace portshutter (furnace port open/close mechanism) 147. Note that a structureof the processing furnace 202 will be described later.

A boat elevator (substrate holding tool elevation mechanism) 115, beingan elevation mechanism for elevating the boat 217 and carrying it toinside/outside of the processing furnace 202, is provided in a lowerpart of the processing furnace 202. An arm 128, being a connecting tool,is formed on an elevating stand of the boat elevator 115. A seal cap 219is provided on the arm 128, as a lid member, for vertically supportingthe boat 217 and air-tightly sealing the lower end portion of theprocessing furnace 202 when the boat 217 is elevated by the boatelevator 115.

The boat 217 includes a plurality of holding members, so that aplurality of (for example, about 50 to 150) wafers 200 are horizontallyheld respectively, in a state of being arranged in a vertical direction,with centers thereof aligned.

A clean unit 134 a including a supply fan and a dust-proof filter isprovided above the cassette shelf 105. The clean unit 134 a isconstituted so that clean air, being cleaned atmosphere, is flown intothe casing 111.

Further, a clean unit 134 b including the supply fan and the dust-prooffilter for supplying clean air is installed on a left side end portionof the casing 111, on the opposite side to the side of the wafertransfer device elevator 125 b and the boat elevator 115. The clan airblown out from the clean unit 134 b is circulated around the wafertransfer device 125 a and the boat 217, then sucked in an exhaust devicenot shown, and exhausted to the outside of the casing 111.

(2) Operation of the Substrate Processing Apparatus

Next, an operation of the substrate processing apparatus 101 accordingto this embodiment will be described.

Prior to supplying the cassette 110 to the cassette stage 114, thecassette loading/unloading port 112 is opened by the front shutter 113.Thereafter, the cassette 110 is loaded from the cassetteloading/unloading port 112. The cassette 110 is placed on the cassettestage 114, so that the wafer 200 is set in a vertical posture and thewafer charging/discharging port of the cassette 110 is faced upward.Then, the cassette 110 is vertically rotated by 90 degrees toward therear of the casing 111 by the cassette stage 114. As a result, the wafer200 in the cassette 110 is set in a horizontal posture, and the wafercharging/discharging port of the cassette 110 is faced rearward in thecasing 111.

Next, the cassette 110 is automatically carried and transferred to thecassette shelf 105 and a shelf position designated by the spare cassetteshelf 107, then stored temporarily therein, and transferred to thetransfer shelf 123 from the cassette shelf 105 or the spare cassetteshelf 107, or directly carried to the transfer shelf 123.

When the cassette 110 is transferred to the transfer shelf 123, thewafer 200 is picked up from the cassette 110 through the wafercharging/discharging port by the tweezer 125 c of the wafer transferdevice 125 a, and charged into the boat 217 in the rear of the transferchamber 124 by the continuous motion of the wafer transfer device 125 aand the wafer transfer device elevator 125 b. After the wafer 200 istransferred to the boat 217, the wafer transfer device 125 a returns tothe cassette 110 so that the next wafer 200 is charged into the boat217.

When previously designated sheets of wafers 200 are charged into theboat 217, the lower end portion of the processing furnace 202, which isclosed by the furnace port shutter 147, is opened by the furnace portshutter 147. Subsequently, by elevating the seal cap 219 by the boatelevator 115, the boat 217 holding a group of wafers 200 is loaded intothe processing furnace 202.

After loading, arbitrary processing is applied to the wafer 200 in theprocessing furnace 202. This processing will be described later. In areversed procedure to the aforementioned procedure, the wafer 200 andthe cassette 110 are discharged to outside of the casing 111.

(3) Structure of the Processing Furnace

Next, the structure of the processing furnace 202 according to thisembodiment will be described.

FIG. 2 is a vertical sectional view of the processing furnace 202 of thesubstrate processing apparatus according to this embodiment, and FIG. 3is a horizontal sectional view corresponding to the line A-A of theprocessing furnace 202 shown in FIG. 2.

(Processing Chamber)

The processing furnace 202 according to an embodiment of the presentinvention includes the reaction tube 203 and a manifold 209. Thereaction tube 203 is made of a non-metal material having heat resistanceproperty, such as quartz (SiO₂) and silicon carbide (SiC), and is formedinto a cylindrical shape, with an upper end portion closed and a lowerend portion opened. The manifold 209 is made of a metal material such asSUS, and is formed into a cylindrical shape, with the upper end portionand the lower end portion opened. The reaction tube 203 is verticallysupported by the manifold 209 from the side of the lower end portion.The reaction tube 203 and the manifold 209 are concentrically disposed.The lower end portion of the manifold 209 is air-tightly sealed by theseal cap 219 when the aforementioned boat elevator 115 is elevated. AnO-ring 220, being a sealing member, for air-tightly sealing the insideof the processing chamber 201 is provided between the lower end portionof the manifold 209 and the seal cap 219.

The processing chamber 201 accommodating the wafer 200, being thesubstrate, is formed inside of the reaction tube 203. The boat 217,being a substrate holding tool, is inserted into the processing chamber201 from below. Inner diameters of the reaction tube 203 and themanifold 209 are made larger than a maximum outer diameter of the boat217 into which the wafer 200 is charged.

The boat 217 is constituted so that a plurality of (for example 75 to100) wafers 200 are held in multiple stages, with prescribed gaps(substrate pitch intervals) provided in approximately horizontal states.The boat 217 is mounted on a heat insulating cap 218 for insulatingthermal conduction from the boat 217. The heat insulating cap 218 issupported from below by a rotational shaft 255. The rotational shaft 255is provided so as to pass through the center part of the seal cap 219,while an air-tight state of the inside of the processing chamber 201 ismaintained. A rotating mechanism 267 for rotating the rotational shaft255 is provided below the seal cap 219. By rotating the rotational shaft255 by the rotating mechanism 267, the boat 217, on which a plurality ofwafers 200 are mounted, can be rotated, while the air-tight state of theinside of the processing chamber 201 is maintained.

A heater 207, being a heating unit (heating mechanism) is provided on anouter periphery of the reaction tube 203, concentrically with thereaction tube 203. The heater 207 has a cylindrical shape, and isvertically installed on a heater base 207 a by being supported therebyas a holding plate shown in FIG. 3. The wafer 200 and the atmosphere inthe processing chamber are heated by a radiation heat from the heater207.

(Gas Supply Unit)

A first gas supply nozzle 233 a is provided in the manifold 209. Thefirst gas supply nozzle 233 a is formed into an L-shape having avertical portion and a horizontal portion. The vertical portion of thefirst gas supply nozzle 233 a is formed linearly along a loadingdirection of the wafers 200, and is extended from the lower part of theprocessing chamber 201 to the vicinity of a ceiling part of theprocessing chamber 201, through a circular arc shaped space in a planarview, between the inner wall of the reaction tube 203 and the wafer 200on the boat 217. A plurality of first gas jet holes 248 a, being gasinlet ports for introducing gas into the processing chamber 201, arevertically provided on the side face of the vertical portion (cylinderportion) of the first gas supply nozzle 233 a. The first gas jet holes248 a are provided at the same pitch as the pitch of loading the wafer200 held by the boat 217, so that the gas is horizontally flown alongthe upper surface of each wafer 200 on the boat 217. Further, the firstgas jet holes 248 a have mutually the same opening areas, to therebyequalize the flow rate of the gas flowing on each wafer 200. Note thatan opening diameter of each of the first gas jet holes 248 a may be setto be gradually larger from the lower part to the upper part.

The horizontal portion of the first gas supply nozzle 233 a is providedso as to pass through the side wall of the manifold 209. The first gassupply tube 232 a for supplying source gas (TEHAH gas and TEMAZ gas)obtained by vaporizing a liquid source such as tetrakisdimethyl aminohafnium (Hf[NCH₃C₂H₅]₄; TEHAH) and tetrakisdimethyl amino zirconium(TEMAZ) containing element Hf (hafnium) and element Zr (zirconium), isconnected to an upper stream end of the first gas supply nozzle 233 a. Aliquid source supply source, a mass flow controller 240, being a flowrate control device (flow rate controller), a vaporizer 242 forgenerating the source gas by vaporizing the liquid source, and a firstvalve 243 a, are provided in the first gas supply tube 232 a,sequentially from an upper stream.

A first carrier gas supply tube 234 a for supplying N₂ GAS, being acarrier gas (purge gas), is connected to a lower stream side of thefirst valve 243 a of the first gas supply tube 232 a. A carrier gassupply source not shown, a second mass flow controller 241 b, being aflow rate control device (flow rate controller), and a third valve 243 care provided in the first carrier gas supply tube 234 a, sequentiallyfrom the upper stream.

A second gas supply nozzle 233 b is provided in the manifold 209. Thesecond gas supply nozzle 233 b is formed into an L-shape having thevertical portion and the horizontal portion. The vertical portion of thesecond gas supply nozzle 233 b is formed linearly along the loadingdirection of the wafers 200, and is extended from the lower part of theprocessing chamber 201 to the vicinity of the ceiling part of theprocessing chamber 201, through a circular arc shaped space in a planarview, between the inner wall of the reaction tube 203 and the wafer 200on the boat 217. A plurality of second gas jet holes 248 b, being thegas inlet ports for introducing the gas into the processing chamber 201,are vertically provided on the side face of the vertical portion(cylinder portion) of each second gas supply nozzle 233 b. The secondgas jet holes 248 b are provided at the same pitch as the pitch ofloading the wafer 200 held by the boat 217, and are respectively formedso that the gas is horizontally flown along the upper surface of eachwafer 200 on the boat 217. Further, the second gas jet holes 248 b havemutually the same opening areas, to thereby equalize the flow rate ofthe gas flowing on each wafer 200. Note that the opening diameter ofeach of the second gas jet holes 248 b may be set to be gradually largerfrom the lower part to the upper part.

The horizontal portion of the second gas supply nozzle 233 b is providedso as to pass through the side wall of the manifold 209. The second gassupply tube 232 b for supplying ozone (O₃) gas, being the oxide gas, isconnected to the upper stream end of the second gas supply nozzle 233 b.An ozone gas supply source, a first mass flow controller 241 a, beingthe flow rate control device (flow rate controller), and an ozone supplyvalve AV2 are provided in the second gas supply tube 232 b sequentiallyfrom the upper stream.

A vent gas tube 232 v is connected between the mass flow controller 241a of the second gas supply tube 232 b, and the ozone supply valve AV2. Asixth valve 243 v is provided in the vent gas tube 232 v. When the ozonegas is not supplied into the processing chamber 201, the sixth valve 243v is opened and ozone is discharged from the vent gas tube 232 v,without stopping the generation of ozone, to thereby stably and rapidlystart next supply of ozone into the processing chamber 201.

A second carrier gas supply tube 234 b for supplying N₂ gas, being acarrier gas (purge gas), is connected to the lower stream side of theozone supply valve AV2 of the second gas supply tube 232 b. A carriergas supply source not shown, a third mass flow controller 241 c, beingthe flow rate control device (flow rate controller), and a fourth valve243 d are provided in the second carrier gas supply tube 243 b,sequentially from the upper stream.

A source gas supply unit according to this embodiment is mainlyconstituted by the first gas supply nozzle 233 a, the first gas jet hole248 a, the first gas supply tube 232 a, a liquid source supply sourcenot shown, the liquid mass flow controller 240, the vaporizer 242, thefirst valve 243 a, the first carrier gas supply tube 234 a, and thesecond mass flow controller 241 b, and the third valve 243 c. Also, anoxide gas supply unit according to this embodiment is mainly constitutedby the second gas supply nozzle 233 b, the second gas getting port 248b, the second gas supply tube 232 b, an ozone gas supply source notshown, the first mass flow controller 241 a, the ozone supply valve AV2,the vent gas tube 232 v, the sixth valve 243 v, the second carrier gassupply tube 234 b, a carrier gas supply source not shown, the third massflow controller 241 c, and the fourth valve 243 d. In addition, a gassupply unit for supplying the source gas and the oxide gas into theprocessing chamber 201 is mainly constituted by the source gas supplyunit and the oxide gas supply unit.

Thus, the gas supply unit for supplying gas of two kinds (the source gasand the oxide gas) into the processing chamber 201, is provided in thesubstrate processing apparatus 101. Then, a desired film is formed onthe wafer 200, by alternate supply of the gas of two kinds into theprocessing chamber 201. Further, in the film forming step, the inside ofthe processing chamber 201 is cleaned by being exhausted using a vacuumpump 246, after being purged using the carrier gas. Further, desiredprocessing can be performed by replacing a part of the gas supply unitwith a device suitable for processing.

(Exhaust Unit)

An exhaust tube 231 is connected to the side wall of the manifold 209. Afifth valve 243 e, being an exhaust valve, and the vacuum pump 246 areprovided in the exhaust tube 231 sequentially from the upper streamside. Note that the fifth valve 243 e can control start/stop of vacuumexhaust of the processing chamber 201 by opening/closing the valve, andfurther is constituted as an automatic pressure adjustment valve (APCvalve) capable of adjusting a pressure in the processing chamber 201 byadjusting an opening degree of the valve. An exhaust unit for exhaustingthe atmosphere in the processing chamber 201 is mainly constituted bythe exhaust tube 231, the fifth valve 243 e, and the vacuum pump 246.

(Controller)

The substrate processing apparatus according to this embodiment includesa controller 280, being a control part (control means). The controller280 is connected to the liquid mass flow controller 240, first to thirdmass flow controllers 241 a, 241 b, 241 c, first to sixth valves 243 a,243 b, 243 c, 243 d, 243 e, 243 v, the heater 207, the vacuum pump 246,the rotating mechanism 267, and a boat elevating mechanism not shown.The controller 280 is constituted to control flow adjustment operationof the liquid mass flow controller 240 and the first to third mass flowcontrollers 241 a, 241 b, 241 c, open/close operation of the first tofourth and sixth valves 243 a, 243 b, 243 c, 243 d, 243 c, open/closeoperation and opening degree adjustment operation of the fifth valve 243e, temperature adjustment operation of the heater 207, start/stop of thevacuum pump 246, rotating speed adjustment of the rotating mechanism267, and elevating operation of the boat elevating mechanism.

(4) Substrate Processing Step

Next, explanation will be given for the substrate processing stepaccording to this embodiment executed as one of the manufacturing stepsof the semiconductor device. The substrate processing step according tothis embodiment is executed by the aforementioned substrate processingapparatus (normal flow type vertical substrate processing apparatus). Inthe explanation given hereunder, the operation of each part constitutingthe substrate processing apparatus is controlled by the controller 280.

In the substrate processing step according to this embodiment, TEMAH gasis used as the source gas, and ozone gas is used as the oxide gas, tothereby form an HfO₂ film on the wafer 200 by using the ALD method. TheALD method, being one of the CVD methods is a method of forming a filmby supplying on the substrate the reactive gas of two kinds, being atleast sources of two kinds used in film-formation, alternately one byone, which is then adsorbed on the substrate in units of one atom, andfilm-formation is performed by utilizing a surface reaction. At thistime, control of the film thickness is performed by less number ofcycles (for example, if a film forming speed is 1 Å/cycle, the reactivegas is supplied by 20 cycles when a film of 20 Å is formed). In thefilm-formation processing using the ALD method, a processing temperaturefor depositing HfO and ZrO is set to be 180° C. to 270° C., and forexample set to be 250° C. In the ALD method, for example, when the HfO₂film is formed, high quality film-formation is possible at a lowtemperature such as 180 to 250° C. by using the TEMAH gas and the ozonegas.

(Wafer Loading Step)

First, as described above, the wafer 200 is charged into the boat 217,and is loaded into the processing chamber 201. After the boat 217 isloaded into the processing chamber 201, four steps as will be describedlater are sequentially executed.

(Source Gas Supplying Step (Step 1))

In step 1, the TEMAH gas, being the source gas, is supplied into theprocessing chamber 201, while exhausting the atmosphere in theprocessing chamber 201 in which the wafer 200 is accommodated.

Specifically, the fifth valve 243 e of the exhaust tube 231 is opened,and exhaust of the atmosphere in the processing chamber 201 is started.Then, the third valve 243 c of the first carrier gas supply tube 234 ais opened, and the N₂ gas, being the carrier gas, is flown to the firstgas supply tube 232 a, while adjusting the flow rate by the second massflow controller 241 b. Further, TEMAH, being the liquid source, is flownto the vaporizer 242 from the liquid source supply source not shown tobe vaporized, while adjusting the flow rate by the liquid mass flowcontroller 240, to thereby generate the TEMAH gas. Then, the first valve243 a of the first gas supply tube 232 a is opened, and the TEMAH gasgenerated by the vaporizer 242 is flown to the first gas supply nozzle233 a. The TEMAH gas is mixed with the carrier gas in the first gassupply tube 232 a. Mixed gas of the TEMAH gas and the carrier gas issupplied into the processing chamber 201, through the first gas jet hole248 a of the first gas supply nozzle 233 a. Surface reaction (chemicaladsorption) is caused between TEMAH in the mixed gas supplied into theprocessing chamber 201, and a surface part of the wafer 200, to therebyform a base film on the wafer 200. An excess portion of the mixed gasnot contributing to forming the base film, is exhausted from the exhausttube 231 as exhaust gas.

At this time, the opening degree of the fifth valve 243 e is set, sothat the pressure in the processing chamber 201 is set so as to bemaintained in a range of 0.1 to 400 Pa, and for example set to be 200Pa. Further, the flow rate of TEMAH controlled by the liquid mass flowcontroller 240 is set to be 0.01 to 0.1 g/min, and the time for exposingthe wafer 200 to the mixed gas is set to be 30 to 180 seconds. Moreover,the temperature of the heater 207 is adjusted, so that the temperatureof the wafer 200 is set to be in a range of 180 to 250° C. and forexample set to be 230° C.

(Source Gas Removing Step (Step 2))

In step 2, the TEMAH gas and the intermediate body of the TEMAH gasremained in the processing chamber 201 are removed.

Specifically, the first valve 243 a of the first gas supply tube 232 ais closed, and supply of the TEMAH gas into the processing chamber 201is stopped. At this time, the inside of the processing chamber 201 isexhausted by the vacuum pump 246 down to 20 Pa or less, with the fifthvalve 243 e of the exhaust tube 231 opened, and the residual TEMAH gasand intermediate body of the TEMAH gas are removed from the processingchamber 201. Note that the third valve 243 c of the first carrier gassupply tube 234 a is opened until removal of the residual TEMAH gas andintermediate body of the TEMAH gas from the processing chamber iscompleted, and N₂, being purge gas, is supplied into the processingchamber 201 while adjusting its flow rate by using the second mass flowcontroller 241 b. Thus, an effect of removing the residual TEMAH gas andintermediate body of the TEMAH gas from the processing chamber 201 isfurther improved.

(Ozone Supplying Step (Step 3))

In step 3, ozone is supplied into the processing chamber 201, with theexhaust of the atmosphere in the processing chamber 201 substantiallystopped.

Specifically, by closing the fifth valve 243 e of the exhaust tube 231,the exhaust of inside of the processing chamber 201 is substantiallystopped. Then, the fourth valve 243 d of the second carrier gas supplytube 234 b is opened, and the N₂ gas, being the carrier gas, is flown tothe second gas supply tube 232 b, while adjusting its flow rate by usingthe third mass flow controller 241 c. Further, the ozone supply valveAV2 of the second gas supply tube 232 b is opened, and the ozone gas,being the oxide gas, is flown to the second gas supply nozzle 233 b,while adjusting its flow rate by using the first mass flow controller241 a. The ozone gas is mixed with the carrier gas in the second gassupply tube 232 b. The mixed gas of the ozone gas and the carrier gasare supplied into the processing chamber 201 through the second gas jethole 248 b of the second gas supply nozzle 233 b. Ozone in the mixed gassupplied into the processing chamber 201 causes surface reaction withTEMAH which is chemically adsorbed on the surface of the wafer 200, tothereby form the HfO₂ film on the wafer 200. An excess portion of themixed gas not contributing to forming the HfO₂ film is exhausted fromthe exhaust tube 231 as exhaust gas.

At this time, the opening degree of the fifth valve 243 e is set, sothat the pressure in the processing chamber 201 is maintained in a rangeof 0.1 to 400 Pa and for example maintained to be 200 Pa. Further, thetime for exposing the wafer 200 to O₃ is set to be 10 to 120 seconds.Moreover, the temperature of the heater 207 is adjusted, so that thetemperature of the wafer 200 is set to be in a range of 180 to 250° C.in the same way as the time for supplying the TEMAH gas of step 1, andfor example, set to be 230° C.

(Repeating Step)

Thereafter, the aforementioned steps 1 to 4 are set as one cycle, and byrepeating this cycle multiple number of times, the HfO₂ film of desiredthickness is formed on the wafer 200, and the substrate processing stepaccording to this embodiment is ended. Then, the wafer 200 afterprocessing is unloaded from the processing chamber 201, by a procedurereverse to the wafer loading step.

(5) Advantage of this Embodiment

According to this embodiment, one or a plurality of advantages areexhibited, as shown below.

(a) According to this embodiment, the ozone supplying step (step 3) forsupplying ozone into the processing chamber 201 is performed, withexhaust of the atmosphere in the processing chamber 201 substantiallystopped. Thus, ozone is diffused and the inside of the processingchamber 201 is reserved with ozone, so that ozone can be sufficientlysupplied not only to the outer peripheral edge, but also to the centerpart of the wafer 200. As a result, the processing time for forming theHfO₂ film can be shortened, and homogeneity of distribution of thicknessand distribution of composition of the HfO₂ film formed on the wafer 200can be improved.(b) Further, according to this embodiment, the TEMAH gas and ozone arealternately supplied into the processing chamber 201 so as not to bemixed with each other. Thus, excess vapor phase reaction in theprocessing chamber 201 can be suppressed, film forming reaction can beefficiently generated on the wafer 200, and the processing time forforming the HfO₂ film can be shortened. Moreover, generation ofparticles in the processing chamber 201 can be suppressed, andhomogeneity of the distribution of thickness and distribution ofcomposition of the HfO₂ film formed on the wafer 200 can be improved.(c) Moreover, according to this embodiment, the aforementioned advantagecan be obtained, by performing the ozone supplying step (step 3), withexhaust of the atmosphere in the processing chamber 201 substantiallystopped, and there is no necessity for supplying ozone of large flowrate into the processing chamber 201. Therefore, waste of ozone can besuppressed, and cost required for processing substrates can be reduced.

Second Embodiment

Next, a basic structure of the side flow type vertical substrateprocessing apparatus and a substrate processing method using thissubstrate processing apparatus, according to a second embodiment of thepresent invention will be described.

As shown in FIG. 18, the substrate processing apparatus according thisembodiment is different from the substrate processing apparatusaccording to the aforementioned embodiment, in the point that thereaction tube 203 is constituted of an outer tube 31 and an inner tube38 disposed inside of the outer tube 31. In addition, the substrateprocessing apparatus according to this embodiment is different from thesubstrate processing apparatus according to the aforementionedembodiment in the point that a plurality of exhaust ports 41 areprovided on the side wall of the inner tube 38 so that exhaust passedthrough the plurality of exhaust ports 41 is discharged from an exhaustport 35 provided in a lower part of the outer tube 31. Other structureis the same as that of the normal flow type vertical substrateprocessing apparatus.

The side flow type vertical substrate processing apparatus will bedescribed below, focusing on these different points.

FIG. 18 is a vertical sectional view of a side flow type processingfurnace according to this embodiment. As shown in the figure, thereaction tube according to this embodiment is constituted of the outertube 31, and the inner tube 38 disposed inside of the outer tube 31. Theouter tube 31 and the inner tube 38 are respectively made of non-metalmaterials having heat resistance property, such as quartz (SIO₂) andsilicon carbide (SiC), and have a cylindrical shape, with the upper endportion closed and the lower end portion opened. The outer tube 31 isvertically supported by the manifold 209 from the side of the lower endportion. A receiver base 31 a projecting toward inside is formed on aninner wall surface of the lower part of the outer tube 31. A pluralityof projection parts 38 a projecting toward outside are formed on anouter wall surface of the lower part of the inner tube 38. The innertube 38 is vertically supported from below in the outer tube 31, bysetting the projection parts 38 a on the receiver base 31 a. Cylindricalspace 39 extending vertically is formed between the outer wall surfaceof the inner tube 38 and the inner wall surface of the outer tube 31.The processing chamber 201 is formed inside of the inner tube 38, sothat the boat 217 is inserted from below.

The vertical portion of the first gas supply nozzle 233 a and thevertical portion of the second gas supply nozzle 233 b are respectivelyextended to the vicinity of the ceiling part of the processing chamber201, through a circular arc-shaped space in planar view, between theinner wall of the inner tube 38 and the wafer 200 on the boat 217.

A plurality of exhaust ports 41 are provided at positions opposed to thefirst gas supply nozzle 233 a and the second gas supply nozzle 233 b.The plurality of exhaust ports 41 are provided at the same pitch as thepitch of loading the wafer 200 held by the boat 217 (namely, anarrangement pitch of the first gas jet holes 248 a and the second gasjet holes 248 b), so that the gas is horizontally flown along the uppersurface of each wafer 200 on the boat 217. Note that the exhaust port35, with the exhaust tube 231 connected thereto, is formed on the lowerpart of the side wall of the manifold 209 (below the lower end of theinner tube 38).

In addition, a furnace port 34, being an opening, is formed on the lowerend of the manifold 209. The furnace port 34 is constituted so as to besealed by a seal cap 219, being a disc (lid member) having an outerdiameter larger than an inner diameter of the furnace port 34, throughan O-ring (seal ring) 220. In addition, a rotational shaft 64 of therotating mechanism 267 is provided so as to pass through an axial centerpart of the seal cap 219. A support stand is vertically erected on theupper end of the rotational shaft 64. The boat 217, being a substrateholding tool, is vertically erected on the support stand.

When the boat holding a plurality of wafers 200 is inserted into theprocessing chamber 200 and the processing chamber 201 is sealed by theseal cap 219, the inside of the processing chamber 201 is exhausted downto a prescribed pressure or less, by the vacuum pump 246 connected tothe exhaust tube 231, and the temperature inside of the processingchamber 201 is raised to a prescribed temperature. Then, the boat 217 isrotated by a rotational shaft 62 of a rotation driving mechanism 63.With a structure of a hot wall type furnace structure, the temperaturein the processing chamber 201 is maintained uniformly over the whole,and temperature distribution of the boat 217 and each wafer 200 heldthereby is also uniform over the whole.

According to this embodiment, one or a plurality of effects shown beloware further exhibited, in addition to the aforementioned effects.

(a) According to this embodiment, the first gas supply nozzle 233 a, thesecond gas supply nozzle 233 b are provided inside of the inner tube 38,so as to be extended in a loading direction of the plurality of wafers200. Further, a plurality of exhaust ports 41 are provided at positionsof the inner tube 38 opposed to the first gas supply nozzle 233 a andthe second gas supply nozzle 233 b. Thus, a horizontal flow of thesource gas and the oxide gas can be formed over each wafer 200. Then,uniformity in the surface of the HfO₂ film, etc, formed on each wafer200 can be improved.(b) In addition, according to this embodiment, the first gas supplynozzle 233 a and the second gas supply nozzle 233 b are disposed so asto be close to the outer edge of the wafer 200 held by the boat 217.Thus, supply efficiency of the source gas and the oxide gas to the wafer200 can be improved, and productivity of processing substrates can beimproved. In addition, supply amount of the gas to the vicinity of thecenter of the wafer 200 can be increased, and the uniformity in thesurface of the thickness of the HfO₂ film formed on the wafer 200 can beimproved.(c) In addition, according to this embodiment, vertically continuedspace 39 is formed between the outer wall surface of the inner tube 38and the inner wall surface of the outer tube 31. Further, the exhaustport 35 is provided on the lower side of the opening end of the innertube 38. Thus, both of the gas passed through the space 39 between theinner tube 38 and the outer tube 31, and the gas from the opening end ofthe inner tube can be simultaneously exhausted, and replacementefficiency of the gas can be improved.

FIG. 19 is a perspective view showing a modified example of the innertube 38 shown in FIG. 18.

A different point from the substrate processing apparatus explained inFIG. 18 is a point that exhaust port 41A is opened on a ceiling wall ofthe inner tube 38. The exhaust port 41A is provided on the opposite side(the side of a plurality of exhaust ports 41) to the side where theexhaust tube 231 is provided. According to this modified example, thehorizontal flow of the gas jetted from the first gas jet hole 248 a ofthe first gas supply nozzle 233 a, and the gas jetted from the secondgas jet hole 248 b of the second gas supply nozzle 233 b can berespectively suppressed, and gas purge efficiency in the processingchamber 201 can be improved. Note that it is desirable to set the sizeof the exhaust port 41A to be optimum, by comparing a horizontal flowsuppressing effect and the gas purge efficiency.

Third Embodiment

Next, explanation will be given for the structure of the substrateprocessing apparatus according to the third embodiment of the presentinvention, and the substrate processing step executed by this substrateprocessing apparatus.

(1) Structure of the Substrate Processing Apparatus

First, the structure of the substrate processing apparatus according tothis embodiment will be described, with reference to FIG. 4. FIG. 4 is aschematic block diagram of the processing furnace and the gas supplyunit of the substrate processing apparatus according to this embodiment.This embodiment is different from the aforementioned embodiment in thepoint that the ozone gas, being the oxide gas, is supplied into theprocessing chamber 201 pulsatively by the gas supply unit (flushsupply). Note that the structure other than the gas supply unit is thesame as that of the first embodiment, excluding an oxidation sequence ofthe controller 280. The structure of the gas supply unit of thesubstrate processing apparatus according to this embodiment will bedescribed hereinafter.

As shown in FIG. 4, a lower stream end of the first gas supply tube 232a is connected to the upper stream end of the first gas supply nozzle233 a. The upper stream end of the first gas supply tube 232 a isconnected to the secondary side (outlet) of a vaporizing chamber 242 aformed in the vaporizer 242. The lower stream end of a transfer tube 100is connected to the primary side (inlet) of the vaporizing chamber 242a. The upper stream end of the transfer tube 100 is inserted (immersed)into the TEMAH, being a liquid source stored in a tank 305 as a liquidsource supply source. A valve AV4 and the liquid mass flow controller240 are provided in the transfer tube 100 sequentially from the upperstream side. The lower stream end of a compressed gas supply tube 51 isconnected to an upper space of the TEMAH stored in the tank 305, so thatthe N₂ gas, being the compressed gas, is supplied from the compressedgas supply tube 51. A valve AV3 is provided in the compressed gas supplytube 51. The lower stream end of the first carrier gas supply tube 234 ais connected to the inside of the vaporizing chamber 242 a, so that theN₂ gas, being the carrier gas (purge gas) is supplied thereto. A carriergas supply source not shown, the second mass flow controller 241 b, andthe third valve 243 c are provided sequentially from the upper streamside, in the first carrier gas supply tube 234 a. A switching valve 50is provided in the vaporizer 242. By this switching valve 50, switchingis possible to either one of a switching position (called a carrier gassupply position hereinafter) for communicating the inside of the tank305 and the vaporizing chamber 242 a, and a switching position (called acarrier gas supply position) for communicating the first carrier gassupply tube 234 a and the first gas supply tube 232 a through thevaporizing chamber 242 a.

The lower stream end of the second gas supply tube 232 b is connected tothe upper stream end of the second gas supply nozzle 233 b. An ozonizer52, being an ozone generating apparatus, an ozone inlet valve AV1, thefirst mass flow controller 241 a, a buffer tank 102, being a gasreservoir connected to the processing chamber 201, and an ozone supplyvalve AV2 are provided in the second gas supply tube 232 b. The ozonizer52 is an apparatus for generating ozone gas from oxygen (O₂) bydischarge. Oxygen gas is supplied to the ozonizer 52 from an oxygen gassupply line not shown. The buffer tank 102, being the gas reservoir, isconstituted as a pressure vessel temporarily charged with ozone gassupplied into the processing chamber 201 pulsatively. Namely, after theinside of the buffer tank 102 is temporarily charged with ozone gassupplied from the ozonnizer 52, this ozone gas is supplied(flush-supplied) into the processing chamber 201 pulsatively. Note thatin this embodiment, the second carrier gas supply tube 234 b is removed,unlike the substrate processing apparatus according to the firstembodiment.

Regarding the source gas generated by vaporization of the liquid sourcein the vaporizer 242, re-liquefaction is apt to occur depending on itstype. Therefore, a supply route of the source gas (the upper stream sideof the first gas supply tube 232 a and the first gas supply nozzle 233a) to the processing chamber 201 from the secondary side of thevaporizer 242 (outlet) is heated to a prescribed temperature (forexample, 130° C. when TEMAZ is used as the liquid source), to therebysuppress the re-liquefaction of the source gas. Specifically, a ribbonheater (not shown), etc, is provided on an outer surface of theaforementioned supply route of the source gas (the upper stream side ofthe first gas supply tube 232 a and the first gas supply nozzle 233 a).

In addition, in order to accelerate vaporization of the liquid source inthe vaporizer 242, the supply route (transfer tube 100) of the liquidsource from the tank 305 to the vaporizer 242 is heated to a prescribedtemperature, to thereby preheat the liquid source supplied to thevaporizer 242. Specifically, the ribbon heater (not shown), etc, isprovided on the outer surface of the supply route (transfer tube 100) ofthe liquid source.

Note that when the ribbon heater (not shown) is provided on the outersurface of the supply route (the upper stream side of the transfer tube100, the first gas supply tube 232 a, and the first gas supply nozzle233 a) of the liquid source and the source gas, to thereby heat theinside of the supply route, the inside of the buffer tank 102 is alsoheated by heat conduction, thus decomposing ozone reserved into thebuffer tank 102. Therefore, the inside of the buffer tank 102 is cooled.For example, as shown in FIG. 15, a cooling coil 300 is provided on theouter surface of the buffer tank 102, and by flowing a heat exchangingmedium such as chilling water and industrial water into the cooling coil300, the buffer tank 102 is cooled. In addition, as shown in FIG. 16, itis also acceptable that the buffet tank 102 is provided inside of athermostatic bath 301, and the temperature of the inside of thethermostatic bath 301 is kept to be within a range of −20 to +25° C.,for example, around 23° C. Further, although not shown, the buffet tank102 may also be cooled by use of a Peltier element. With this structure,it is possible to suppress a situation in which ozone is decomposed inthe buffer tank 102 before it reaches the processing chamber 201, thenstabilize the supply of the ozone gas into the processing chamber 201,and suppress waste of ozone.

In addition, ozone reserved into the buffer tank 102 is reacted with theinner wall surface of the buffer tank 102, and is deactivated in somecases. Therefore, the inner wall surface of the buffer tank 102 iscoated with a coating film, to thereby suppress the reaction between theinner wall surface of the buffer tank 102 and the ozone gas. Forexample, oxide films of iron (Fe), titanium (Ti), aluminum (Al), nickel(Ni), or chromium (Cr) (Fe oxide film, Ti oxide film, Al oxide film, Nioxide film, and Cr oxide film) can be used as the kind of the coatingfilm. It is also acceptable that an inner surface of the buffer tank 102is coated with a stainless film such as SUS316, or the buffer tank 102is constituted of stainless steel such as SUS316. In a stainless steelcontaining chromium, chromium oxide, etc, is easily formed by oxidationprocessing, and a stable immobility film (oxide film) is thereby formed.Therefore, it is possible to prevent the deactivation of ozone reservedinto the buffer tank 102.

Further, the deactivation of ozone is suppressed not only on the innerwall surface of the buffer tank 102, but also in a supply path of theozone gas, namely, on the inner wall surface of the second gas supplytube 232 b. Specifically, the inner wall surface of the second gassupply tube 232 b is coated with the aforementioned coating film. Inaddition, it is also acceptable that the second gas supply tube 232 b isconstituted of stainless, and the immobility film made of chromium oxideis formed on the inner wall surface of the second gas supply tube 232 b.

In addition, in order to form the immobility film made of chromium oxideon the inner wall surface of the buffer tank 102 and the inner wallsurface of the second gas supply tube 232 b, a coating step is executed,for supplying ozone to the second gas supply tube 232 b from theozonizer 52, in a state of sufficiently removing moisture inside of thebuffer tank 102 and the second gas supply tube 232 b. At this time, theozone inlet valve AV1 and the ozone supply valve AV2 are opened, andother valves are closed. As a result, the surface of each part made ofstainless is exposed to ozone and oxidized, and on this surface, astable immobility film made of chromium oxide, etc, is formed. Thus, thedeactivation of ozone can be suppressed, and wasteful consumption ofozone can be prevented. In addition, the coating step of forming theimmobility film made of chromium oxide on the inner wall surface of thebuffer tank 102 and the inner wall surface of the second gas supply tube232 b may be performed before the substrate processing step as will bedescribed later is started.

(2) Substrate Processing Step

Next, the substrate processing step according to this embodimentexecuted as one of the manufacturing steps of a semiconductor devicewill be described. The substrate processing step according to thisembodiment has an ozone reserving step of reserving ozone into thebuffer tank 102 connected to the processing chamber 201, before theozone supplying step, and in the ozone supplying step, ozone reservedinto the buffer tank 102 is supplied (flush-supplied) pulsatively intothe processing chamber 201, and this point is different from the firstand second embodiments. In this embodiment, the ozone filing step, theozone supplying step, and the ozone removing step are repeated multiplenumber of times. The substrate processing step according to thisembodiment is executed by the substrate processing apparatus shown inFIG. 4. In the following explanation, an operation of each partconstituting the substrate processing apparatus is controlled by thecontroller 280.

(Wafer Loading Step)

First, as described above, the wafer 200 is charged into the boat 217,and is loaded into the processing chamber 201. After the boat 217 isloaded into the processing chamber 201, five steps as will be describedlater are sequentially executed.

(Source Gas Supplying Step (Step 1))

In step 1, TEMAH gas, being a source gas, is supplied into theprocessing chamber 201, while exhausting an atmosphere in the processingchamber 201 in which the wafer 200 is accommodated.

Specifically, the fifth valve 243 e of the exhaust tube 231 is opened,and exhaust of the atmosphere in the processing chamber 201 is started.Further, the valve AV3 is opened, and the N₂ gas, being the compressedgas, is supplied to an upper space of the TEMAH stored in the tank 305.Moreover, the switching valve 50 is formed at a source gas supplyingposition, then the valve AV4 is opened, and TEMAH stored in the tank 305is fed to the vaporizer 242 (vaporizing chamber 242 a) in a compressedstate, with its flow rate adjusted by the liquid mass flow controller240, to thereby generate the TEMAH gas. Further, the first valve 243 aof the first gas supply tube 232 a is opened, and the N₂ gas, being thecarrier gas, is supplied to the vaporizer 242 (vaporizing chamber 242a), with its flow rate adjusted by the second mass flow controller 241b. As a result, mixed gas of the TEMAH gas and the carrier gas issupplied into the processing chamber 201, through the first gas jet hole248 a of the first gas supply nozzle 233 a. The TEMAH in the mixed gassupplied into the processing chamber 201 causes surface reaction(chemical adsorption) with a surface part, etc, of the wafer 200, and abase film is formed on the wafer 200. An excess portion of the mixed gasnot contributing to forming the base film is exhausted from the exhausttube 231 as exhaust gas.

At this time, the opening degree of the fifth valve 243 e is set, sothat the pressure in the processing chamber 201 is maintained in a rangeof 0.1 to 400 Pa, for example, 200 Pa. In addition, the flow rate of theTEMAH controlled by the liquid mass flow controller 240 is set to be0.01 to 0.1 g/min, and the time for exposing the wafer 200 to the mixedgas is set to be 30 to 180 seconds. Further, the temperature of theheater 207 is set, so that the temperature of the wafer 200 is set in arange of 180 to 250° C., and for example, 230° C.

(Source Gas Removing Step (Step 2))

In step 2, the TEMAH gas and the intermediate body of the TEMAH gasremained in the processing chamber 201 are removed.

Specifically, the switching valve 50 of the vaporizer 242 is formed at acarrier gas supplying position, and the supply of the TEMAH gas into theprocessing chamber 201 is stopped. At this time, the inside of theprocessing chamber 201 is exhausted until the pressure becomes 20 Pa orless by using the vacuum pump 246, with the fifth valve 243 e of theexhaust tube 231 opened, and the third valve 243 c of the first carriergas supply tube 234 a is kept open, until the removal of the residualTEMAH gas and intermediate body of the TEMAH gas from the processingchamber 201 is completed, and N₂, being the purge gas, is supplied intothe processing chamber 201, with its flow rate adjusted by the secondmass flow controller 241 b. Thus, an effect of removing the residualTEMAH gas and intermediate body of the TEMAH gas from the processingchamber 201 is further increased.

(Oxide Film Forming Step (Step 3))

Next, an oxide film forming step (step 3) is executed, in which the stepof reserving ozone into the buffer tank 102, being a gas reservoirconnected to the processing chamber 201 (ozone filing step (step 3 a),the step of supplying into the processing chamber 201 ozone reservedinto the buffer tank 102 (step 3 b), and the step of exhausting theatmosphere of the processing chamber 201 (ozone removing step (step 3 c)are repeated multiple number of times.

Sequence examples 1 to 3 of the oxide film forming step (step 3) arerespectively shown in FIG. 6 to FIG. 8.

(Sequence Example 1)

FIG. 6 shows a sequence example 1 of the oxide film forming step (step3).

In the sequence example 1, as shown in [1] of FIG. 6, the ozone inletvalve AV1 is opened, with the fifth valve (APC) 243 e opened, and theozone supply valve AV2 closed, and ozone gas is supplied into the buffertank 102, with its flow rate adjusted by the first mass flow controller241 a (ozone reserving step (step 3 a).

When a prescribed time is elapsed, then a prescribed amount of the ozonegas is reserved into the buffer tank 102, and the pressure in the buffertank 102 reaches, for example, 100000 Pa, as shown in [2] of FIG. 6, theozone supply valve AV2 is opened, and the ozone gas reserved into thebuffer tank 102 is supplied into the processing chamber 201 (ozonesupplying step (step 3 b). In the ozone supplying step (step 3 b), theozone gas reserved into the buffer tank 102 is supplied (flush-supplied)into the processing chamber 201 pulsatively. The ozone gas causessurface reaction with TEMAH which is chemically adsorbed on the surfaceof the wafer 200, to thereby form the HfO₂ film on the wafer 200. Inaddition, in the ozone supplying step (step 3 b), the pressure in theprocessing chamber 201 immediately after supplying ozone is set to be,for example, within a range of 0.1 to 1000 Pa.

After a prescribed time is elapsed, ozone and the intermediate body ofozone remained in the processing chamber 201 are removed (ozone removingstep (step 3 c). Specifically, the ozone supply valve AV2 of the secondgas supply tube 232 b is closed, and the supply of the ozone gas intothe processing chamber 201 is stopped. At this time, the inside of theprocessing chamber 201 is exhausted by the vacuum pump 246 until thepressure thereof becomes 20 Pa or less, with the fifth valve 243 e ofthe exhaust tube 231 opened, and the residual ozone and intermediatebody of ozone are removed from the processing chamber 201. Note that ifthe fourth valve 243 d of the second carrier gas supply tube 234 b areopened until removal of the residual ozone and intermediate body ofozone from the processing chamber 201 is completed and in this state,when N₂, being purge gas, is supplied into the processing chamber 201,with its flow rate adjusted by the third mass flow controller 241 c, theeffect of removing the residual ozone and intermediate body of ozonefrom the processing chamber 201 can be further increased.

Then, the ozone reserving step (step 3 a), the ozone supplying step(step 3 b), and the ozone removing step (step 3 c) are set as one cycle,and this cycle is repeated multiple number of times.

(Sequence Example 2)

FIG. 7 shows a sequence example 2 of the oxide film forming step (step3). In the sequence example 2, the exhaust inside of the processingchamber 201 is stopped, when the ozone supplying step (step 3 b) isexecuted.

In the sequence example 2, first, as shown in [1] of FIG. 7, the ozoneinlet valve AV1 is opened, with the fifth valve (APC) 243 e opened andthe ozone supply valve AV2 closed, and the ozone gas is supplied intothe buffer tank 102, with its flow rate adjusted by the first mass flowcontroller 241 a (ozone reserving step (step 3 a)).

After a prescribed time is elapsed, when a prescribed amount of ozonegas is reserved into the buffer tank 102, and the pressure in the buffertank 102 reaches, for example, 100000 Pa, as shown in [2] of FIG. 7, thefifth valve (APC) 243 e is closed, and the ozone supply valve AV2 isopened, and the ozone gas reserved into the buffer tank 102 is suppliedinto the processing chamber 201 (ozone supplying step (step 3 b)). Inthe ozone supplying step (step 3 b), the ozone gas reserved into thebuffer tank 102 is supplied (flush-supplied) into the processing chamber201 pulsatively. The ozone gas causes surface reaction with TEMAH whichis chemically adsorbed on the surface of the wafer 200, to thereby formthe HfO₂ film on the wafer 200. In addition, in the ozone supplying step(step 3 b), the pressure in the processing chamber 201 immediately aftersupplying ozone is set to be, for example, within a range of 0.1 to 1000Pa.

Thereafter, in the same way as the sequence example 1, the ozoneremoving step (step 3 c) is executed. Then, the ozone reserving step(step 3 a), the ozone supplying step (step 3 b), and the ozone removingstep (step 3 c) are set as one cycle, and this cycle is repeatedmultiple number of times.

(Sequence Example 3)

FIG. 8 shows a sequence example 3 of the oxide film forming step (step3). In the sequence example 3, the opening degree of the fifth valve(APC) 243 e is adjusted when the ozone supplying step (step 3 b) isexecuted, and the ozone gas is supplied into the processing chamber 201,while adjusting the pressure in the processing chamber 201 to be anaverage pressure.

In the sequence example 2, first, as shown in [1] of FIG. 8, the ozoneinlet valve AV1 is opened, with the fifth valve (APC) 243 e opened andthe ozone supply valve AV2 closed, and the ozone gas is supplied intothe buffer tank 102, with its flow rate adjusted by the first mass flowcontroller 241 a (ozone reserving step (step 3 a).

After a prescribe time is elapsed, when a prescribed amount of ozone gasis reserved into the buffer tank 102, and the pressure in the buffertank 102 reaches, for example, 100000 Pa, as shown in [2] of FIG. 8, theopening degree of the fifth valve (APC) 243 e is adjusted, and the ozonesupply valve AV2 is opened, to thereby supply into the processingchamber 201 the ozone gas reserved into the buffer tank 102 (ozonesupplying step (step 3 b). In the ozone supplying step (step 3 b), theozone gas reserved into the buffer tank 102 is supplied (flush-supplied)into the processing chamber pulsatively. The ozone gas causes surfacereaction with TEMAH which is chemically adsorbed on the surface of thewafer 200, to thereby form the HfO₂ film on the wafer 200. In addition,in the ozone supplying step (step 3 b), the pressure in the processingchamber 201 immediately after supplying ozone is set in a range, forexample 0.1 to 1000 Pa.

Thereafter, in the same way as the sequence example 1, the ozoneremoving step (step 3 c) is executed. Then, the ozone reserving step(step 3 a), the ozone supplying step (step 3 b), and the ozone removingstep (step 3 c) are set as one cycle, and this cycle is repeatedmultiple number of times.

Note that in any one of the sequence examples, the ozone reserving step(step 3 a) executed at least in an initial time of repetition isexecuted simultaneously with the aforementioned source gas supplyingstep (step 1) and/or the source gas removing step (step 2). Namely, thestep 3 a is executed simultaneously with the source gas supplying step(step 1), simultaneously with the source gas removing step (step 2), orsimultaneously with the source gas supplying step (step 1) and thesource gas removing step (step 2). In addition, the ozone reserving step(step 3 a) executed in a second time of repetition may also be executedsimultaneously with the ozone removing step (step 3 c). Namely, afterthe ozone supplying step (step 3 b) is executed, the timing ofrestarting the reserving of the ozone gas into the buffer tank 102 maybe set after execution of the ozone supplying step (step 3 b) iscompleted.

Further, in any one of the sequence examples, the temperature of thesecond gas supply tube 232 b connecting the buffer tank 102 and theprocessing chamber 201 to a second temperature, while heating the wafer200 to a first temperature (in a range of 180 to 250° C., and forexample 230° C.), and further the temperature of the buffer tank 102 iscooled to a third temperature. At this time, the first temperature isset to be higher than the second temperature, and the second temperatureis set to be higher than the third temperature. Thus, it is possible toprevent ozone from being decomposed in the buffer tank 102.

(Repeating Step)

Thereafter, the aforementioned source gas supplying step (step 1) to theoxide film forming step (step 3) are set as one cycle, and this cycle isrepeated multiple number of times, to thereby form the HfO₂ film of aprescribed thickness on the wafer 200, and the substrate processing stepaccording to this embodiment is ended. Then, the wafer 200 afterprocessing is unloaded from the processing chamber 201, in a reversedprocedure to the aforementioned procedure.

Note that in this embodiment, a volume ratio of the buffer tank 102 tothe processing chamber 201 is set to be, for example, 1/2100 to 1/105.For example, when the volume of the processing chamber 201 is set to be210 L, the volume of the buffer tank 102 is set to be 0.1 L to 2 L. Thisis because when the volume ratio becomes under 1/2100, a flow speed ofthe ozone gas supplied into the processing chamber 201 pulsativelybecomes almost the same as the flow speed of the ozone gas when thebuffer tank 102 is not used, and the effect obtained by using the buffertank 102 is hardly obtained. Also, this is because when the volume ratioexceeds 1/105, the pressure in the processing chamber 201 becomes toohigh, when the ozone gas is supplied into the processing chamber 201from the buffer tank 102 pulsatively, and this is not preferable.

Further, the pressure of the ozone gas reserved into the buffer tank 102is set in a range of 200 to 101, 130 Pa, and set to be, for example,100000 Pa. This is because when the pressure of the ozone gas reservedinto the buffer tank 102 becomes under 200 Pa, the flow speed of theozone gas pulse-supplied into the processing chamber 201 becomes almostthe same as the flow speed of the ozone gas when the buffer tank 102 isnot used, and the effect obtained by using the buffer tank 102 is hardlyobtained. Also, when the pressure of the ozone gas reserved into thebuffer tank 102 exceeds 101, 130 Pa, a differential pressure between apressure of supplying the ozone gas into the processing chamber 201 anda pressure of the ozone gas reserved into the buffer tank 102, is nottaken when the ozone gas is supplied into the processing chamber 201pulsatively, thus making it impossible to control the flow rate. This isnot preferable.

Further, the pressure in the processing chamber 201 during executing theozone supplying step (step 3 b) is set to be 0.1 to 1000 Pa. This isbecause when the pressure of the processing chamber 201 during executingthe ozone supplying step (step 3 b) becomes under 0.1 Pa, ozone supplyto the surface of the wafer 200 becomes insufficient. Moreover, this isbecause when the pressure in the processing chamber 201 during executingthe ozone supplying step (step 3 b) becomes 1000 Pa or more, an exhaustspeed of the vacuum pump 246 is decreased.

(3) Effect According to this Embodiment

According to this embodiment, one or a plurality of effects as shownbelow are further exhibited, in addition to the aforementioned effect.

(a) According to this embodiment, the ozone reserving step (step 3 a)for reserving ozone into the buffer tank 102, being a gas reservoir, isexecuted, before the ozone supplying step (step 3 b). Then, in the ozonesupplying step (step 3 b), ozone reserved into the buffer tank 102 issupplied (flush-supplied) into the processing chamber 201 pulsatively.Thus, a supply amount of ozone to the wafer 200 is increased, and delayin oxidation of the base film in the center part of the wafer 200 issuppressed. Then, uniformity of the film thickness distribution and thecomposition distribution of the HfO₂ film formed on the surface of thewafer 200 is improved, and a manufacturing yield of the semiconductordevice can be improved.(b) In addition, according to this embodiment, the supply amount ofozone to the wafer 200 is increased, without supplying a large flow rateof the oxide gas containing high density ozone to the wafer 200, anddelay in oxidation of the base film in the center part of the wafer 200can be suppressed. Therefore, waste of ozone is suppressed, then thecost of processing substrates can be reduced, and throughput(productivity) of processing substrates can be improved.(c) Further, according to this embodiment, a ribbon heater (not shown),etc, is provided on an outer surface of a supply route of the source gasfrom the secondary side (outlet) of the vaporizer 242 to the processingchamber 201 (the upper stream side of the first gas supply tube 232 aand the first gas supply nozzle 233 a), to thereby heat the source gasto a prescribed temperature (for example, 130° C. when TEMAZ is used asthe liquid source). Thus, re-liquefaction of the source gas can besuppressed.(d) Further, according to this embodiment, the ribbon heater (notshown), etc, is provided on the outer surface of the supply route of theliquid source from the tank 305 to the vaporizer 242, to thereby heatthe liquid source to a prescribed temperature. Thus, vaporization of theliquid source in the vaporizer 242 can be accelerated.(e) Moreover, according to this embodiment, for example as shown in FIG.15, a cooling coil 300 is provided on the outer surface of the buffertank 102, then chilling water and a thermal exchange medium such asindustrial water, etc, is flown into the cooling coil 300, to therebycool the buffer tank 102. Thus, temperature increase of the buffer tankdue to thermal conduction can be suppressed, and decomposition of ozonein the buffer tank 102 can be suppressed before ozone reaches theprocessing chamber 201. Then, supply of the ozone gas into theprocessing chamber 201 can be stabilized and waste of ozone can besuppressed.

EXAMPLES

First, examples 1 to 3 of the present invention will be describedtogether with comparative examples.

FIG. 9 is a table chart explaining examples 1 to 3 of the presentinvention, together with comparative example 1, showing the filmthickness of an average oxidation film, the film thickness of asubstrate center part film, and uniformity of the film thickness.

Example 1

In this example, the sequence of the oxide film forming step (step 3) isthe same as the aforementioned sequence example 1 (FIG. 6). Then, thetime for reserving the ozone gas into the buffer tank 102 is set to be 3seconds, the time for flowing the ozone gas into the processing chamber201 from the buffer tank 102 is set to be 2 seconds, steps from theozone reserving step (step 3 a) to the ozone removing step (step 3 c)are repeated 36 times, and the time for executing the oxide film formingstep (step 3) is set to be 180 seconds in total. The flow rate of the O₃adjusted by the first mass flow controller (MFC) 241 a and supplied intothe buffer tank 102 is set to be constant 9 slm.

Example 2

In this example, the sequence of the oxide film forming step (step 3) isthe same as the aforementioned sequence example 2 (FIG. 7). Namely, inthe ozone supplying step (step 3 b), the fifth valve (exhaust valve) 243e is closed. The other conditions are the same as those of example 1.

Example 3

In this example, the sequence of the oxide film forming step (step 3) isthe same as the aforementioned sequence example 3 (FIG. 8). Namely, inthe ozone supplying step (step 3 b), the opening degree of the fifthvalve (exhaust valve) 243 e is adjusted, and the pressure in theprocessing chamber 201 is adjusted to be an average pressure. The otherconditions are the same as those of the example 1.

Comparative Example 1

In this comparative example, as shown in FIG. 5, the ozone gas iscontinuously supplied into the processing chamber 201, without reservingthe ozone gas into the buffer tank 102. FIG. 5 is a sequence view of theoxide film forming step according to a comparative example. Namely, thevalve AV1 and the valve AV2 are simultaneously opened, and the oxidefilm is formed without executing the ozone reserving step (step 3 a)(without supplying the ozone gas pulsatively).

According to FIG. 9, in each case of the examples 1 and 2, the thicknessof the HfO₂ film is larger than that of the comparative example 1, andthis reveals that a high film forming speed can be obtained. Also, ineach case of the examples 1, 2, 3, the thickness of the HfO₂ film islarger than that of the comparative example 1 in the center part of thewafer 200, and this reveals that the delay in oxidation of the base filmin the center part of the wafer 200 can be suppressed. Also, in eachcase of the examples 1, 2, 3, it is found that the uniformity of thefilm thickness is improved, compared with the comparative example 1. Inaddition, in the examples 1, 2, it is found that the film forming speedis higher, the film thickness is larger in the center part of the wafer200, and the uniformity of the film thickness is higher than those ofexample 3.

Next, examples 4 to 6 of the present invention will be described,together with a comparative example 2.

FIG. 10 is a graph chart explaining the examples 4 to 6 of the presentinvention together with the comparative example 2, wherein FIG. 10Ashows a relation between an average film thickness increase amount ofthe oxide film in the surface of the substrate and an oxidation time,and FIG. 10B shows a relation between the film thickness increase amountof the oxide film in the center part of the substrate and the oxidationtime, respectively.

Example 4

In this example, the sequence of the oxide film forming step (step 3) isthe same as the aforementioned sequence example 1 (FIG. 6). Then, thenumber of repetitions from the ozone filing step (step 3 a) to the ozoneremoving step (step 3 c) is changed, to thereby change the executiontime (oxidation time) of the oxide film forming step (step 3) in such amanner as 60 seconds, 120 seconds, and 180 seconds.

Example 5

In this example, the sequence of the oxide film forming step (step 3) isthe same as the aforementioned sequence example 2 (FIG. 7). Namely, inthe ozone supplying step (step 3 b), the fifth valve (exhaust valve) 243e is closed. Then, the number of repetitions from the ozone reservingstep (step 3 a) to the ozone removing step (step 3 c) is changed, tothereby change the execution time (oxidation time) of the oxide filmforming step (step 3) in such a manner as 60 seconds, 120 seconds, and180 seconds.

Example 6

In this example, the sequence of the oxide film forming step (step 3) isthe same as the aforementioned sequence example 3 (FIG. 8). Namely, inthe ozone supplying step (step 3 b), the opening degree of the fifthvalve (exhaust valve) 243 e is adjusted, to thereby adjust the pressureof the processing chamber 201 to an average pressure (230 Pa). Then, thesteps from the ozone reserving step (step 3 a) to the ozone removingstep (step 3 c) are repeated, and the oxidation time is set to be 180seconds.

Comparative Example 2

In this comparative example, as shown in FIG. 5, the ozone gas is notreserved into the buffer tank 102 but continuously supplied into theprocessing chamber 201. FIG. 5 is a sequence view of the oxide filmforming step according to the comparative example. Namely, the valve AV1and the valve AV2 are simultaneously opened, to thereby form the HfO₂film without executing the ozone reserving step (step 3 a) (withoutsupplying the ozone gas pulsatively). The valve AV1 and the valve AV2are simultaneously opened, to thereby change the time (oxidation time)for supplying the ozone gas in such a manner as 60 seconds, 120 seconds,and 180 seconds.

According to FIG. 10A, in a case of the comparative example 2, it isfound that the oxidation time of about 180 seconds is required forincreasing the average film thickness of the HfO₂ film by 3.5 Å.Meanwhile, in each case of the examples 4, 5, 6 also, it is found that ashort oxidation time is enough to increase the average film thickness ofthe HfO₂ film by 3.5 Å. For example, it is found that the oxidation timeof about 60 seconds is enough in a case of the example 4, to increasethe average film thickness of the HfO₂ film by 3.5 Å, and in a case ofthe example 5, the oxidation time of about 40 seconds is enough. Namely,in each case of the examples 4 to 6, it is found that a higher filmforming speed can be obtained, compared with the comparative example 2.

Further, according to FIG. 10B, in a case of the comparative example 2,even if the oxidation time is increased from 60 seconds to 180 seconds,the thickness of the oxide film in the center part of the substrate ishardly increased (0.1 to 0.2 Å). Meanwhile, in examples 4 and 5, it isfound that the thickness of the HfO₂ film in the center part of thewafer 200 is relatively largely increased (1 to 2 Å), by increasing theoxidation time from 60 seconds to 180 seconds. Namely, in each case ofthe examples 4 and 5 also, the delay of the oxidation of the base filmin the center part of the wafer 200 can be suppressed.

Next, examples 7 and 8 of the present invention will be describedtogether with the comparative example 3.

FIG. 11 is a table chart describing examples 7 and 8 of the presentinvention together with the comparative example 3, and showing theaverage thickness of the HfO₂ film and the uniformity of the filmthickness, in each case of an upper part and a lower part of substrateprocessing positions.

Example 7

In this example, the sequence of the oxide film forming step (step 3) isthe same as the aforementioned sequence example 2 (FIG. 7). Namely, inthe ozone supplying step (step 3 b), the fifth valve (exhaust valve) 243e is closed. Then, by an ALD method wherein the steps from the sourcegas supplying step (step 1) to the oxide film forming step (step 3) areset as one cycle, and this cycle is repeated multiple number of times,the HfO₂ film of a prescribed thickness is formed on the substrate.

Example 8

In this example, the sequence of the oxide film forming step (step 3) isthe same as the aforementioned sequence example 3 (FIG. 8). Namely, inthe ozone supplying step (step 3 b), the opening degree of the fifthvalve (exhaust valve) 243 e is adjusted, to thereby adjust the pressurein the processing chamber 201 to an average pressure. Then, by the ALDmethod wherein the steps from the source gas supplying step (step 1) tothe oxide film forming step (step 3) are set as one cycle, and thiscycle is repeated multiple number of times, the HfO₂ film of aprescribed thickness is formed on the substrate.

Comparative Example 3

In this comparative example, as shown in FIG. 5, the ozone gas iscontinuously supplied into the processing chamber 201, without filingthe ozone gas into the buffer tank 102. FIG. 5 is a sequence view of theoxide film forming step according to the comparative example. Namely,the valve AV1 and the valve AV2 are simultaneously opened, and the HfO₂film is formed by the ALD method, without executing the ozone filingstep (step 3 a) (without supplying the ozone gas pulsatively).

According to FIG. 11, in each case of the examples 7 and 8 also, it isfound that the uniformity of the film thickness is improved, comparedwith the comparative example 3. Note that the film thickness of theexamples 7 and 8, and the film thickness of the comparative example 3are different from each other. However this is because the number ofcycles of ALD is smaller than the number of cycles of ALD of thecomparative example 3, and this is not because the film forming speed ofthe examples 7 and 8 is lower than the film forming speed of thecomparative example 3.

Next, examples 9 and 10 of the present invention will be described,together with the comparative example 4.

FIG. 12 is a table chart showing the composition uniformity of the HfO₂film in each of the upper part, middle part, and lower part of thesubstrate processing positions, wherein FIG. 12A shows the compositionuniformity of the comparative example 4, FIG. 12B shows the compositionuniformity of the example 9, and FIG. 13C shows the compositionuniformity of the example 10, respectively. Note that in any one of thecases, evaluation of the composition uniformity is performed by XPS.

Example 9

In this example, the sequence of the oxide film forming step (step 3) isthe same as the aforementioned sequence example 2 (FIG. 7). Namely, inthe ozone supplying step (step 3 b), the fifth valve (exhaust valve) 243e is closed. Then, by the ALD method wherein the steps from the sourcegas supplying step (step 1) to the oxide film forming step (step 3) areset as one cycle, the HfO₂ film of a prescribed thickness is formed onthe substrate.

Example 10

In this example, the sequence of the oxide film forming step (step 3) isthe same as the aforementioned sequence example 3 (FIG. 8). Namely, inthe ozone supplying step (step 3 b), the opening degree of the fifthvalve (exhaust valve) 243 e is adjusted, to thereby adjust the pressurein the processing chamber 201 to an average pressure. Then, by the ALDmethod wherein the steps from the source gas supplying step (step 1) tothe oxide film forming step (step 3) are set as one cycle, the HfO₂ filmof a prescribed thickness is formed on the substrate.

Comparative Example 4

In this comparative example, the ozone gas is continuously supplied intothe processing chamber 201, without filing the ozone gas into the buffertank 102. Namely, the valve AV1 and the valve AV2 are simultaneouslyopened, and the HfO₂ film is formed by the ALD method, without executingthe ozone reserving step (step 3 a) (without supplying the ozone gaspulsatively).

According to FIG. 12, in a case of the comparative example 4, it isfound that the composition uniformity is deteriorated (deteriorated from±1.40% to ±3.00%), toward the upper part from the lower part of thesubstrate processing positions. Namely, in the case of the comparativeexample 4, it is found that the ozone supply amount to the center partof the wafer is decreased toward the upper part from the lower part ofthe substrate processing positions. Meanwhile, in each case of theexamples 9 and 10, high composition uniformity can be obtained even ifthe substrate processing positions are changed (±0.9 to ±1.0% in thecase of the example 9, and ±1.25% in the case of the example 10).Namely, in either case of the examples 9 and 10, it is found that theozone supply amount to the center part of the wafer can be preventedfrom being decreased toward the upper part from the lower part of thesubstrate processing positions.

Fourth Embodiment

Next, the structure of the substrate processing apparatus according to afourth embodiment of the present invention, and a substrate processingstep executed by this substrate processing apparatus will be described.

(1) Structure of the Substrate Processing Apparatus

First, the structure of the substrate processing apparatus according tothis embodiment will be described, with reference to FIG. 13. FIG. 13 isa schematic block diagram of a processing furnace and a gas supply unitof the substrate processing apparatus according to this embodiment. Inthis embodiment, the gas supply unit includes a plurality of ozone gassupply routes from the ozonizer 52 to the second gas supply nozzle 233b, and these plurality of ozone gas supply routes are provided inparallel. This point is a different point from the third embodiment.Note that other structure is the same as the structure of the thirdembodiment excluding an oxidation sequence of the controller 280. Thestructure of the gas supply unit according to this embodiment will bedescribed hereinafter.

As shown in FIG. 13, the lower stream end of the second gas supply tube232 b is connected to the upper stream end of the second gas supplynozzle 233 b. The second gas supply tube 232 b is branched into aplurality of branch lines (N lines in FIG. 13) in parallel, in thevicinity of a midstream. Each branch line thus branched is merged andunified again on the upper stream side and is connected to the ozonizer52. Ozone inlet valves AV1-1 to AV1-N, first mass flow controllers 241a-1 to 241 a-N, buffer tanks 102-1 to 102-N, being the gas reservoirconnected to the processing chamber 201, and ozone supply valves AV2-1to AV2-N are respectively provided sequentially from the upper streamside, in each branch line formed by branching the second gas supply tube232 b.

By closing the ozone supply valves AV2-1 to AV2-N, and opening the ozoneinlet valves AV1-1 to AV1-N, the ozone gas can be reserved into thebuffer tanks 102-1 to 102-N, while adjusting the flow rate by the firstmass flow controllers 241 a-1 to 241 a-N. Thereafter, by sequentiallyopening the ozone supply valves AV2-1 to AV2-N, the ozone gas reservedinto the buffer tanks 102-1 to 102-N can be supplied (flush-supplied)into the processing chamber 201 pulsatively. Further, by controlling atime interval for opening the ozone supply valves AV2-1 to AV2-N, thetime interval for pulse-supply is narrowed, so that an oxidationprocessing speed can be increased.

(2) Substrate Processing Step

Next, the substrate processing step according to this embodimentexecuted as one of the manufacturing steps of the semiconductor devicewill be described, with reference to FIG. 14. FIG. 14 is a viewexemplifying an operation of the gas supply unit according to thisembodiment, and a valve open/close sequence. According to the substrateprocessing step of this embodiment, in the oxide film forming step (step3), the ozone gas, being the oxide gas, is sequentially supplied(flush-supplied) into the processing chamber 201 pulsatively, from aplurality of ozone supply routes provided in parallel. This point is adifferent point from the third embodiment. The substrate processing stepaccording to this embodiment is executed by the substrate processingapparatus shown in FIG. 13. In the following description, the operationof each part constituting the substrate processing apparatus iscontrolled by the controller 280.

(Wafer Loading Step to Source Gas Removing Step (Step 2))

First, in the same way as the aforementioned embodiments, the waferloading step, the source gas supplying step (step 1), and the source gasremoving step (step 2) are sequentially executed.

(Oxide Film Forming Step (Step 3))

Next, the oxide film forming step (step 3) is executed. Note that in theoxide film forming step (step 3) exemplified in FIG. 14, by using anozone supply system of three systems, the ozone gas is sequentiallysupplied (flush-supplied) into the processing chamber 201 pulsatively.

First, as shown in [1] of FIG. 14, the ozone supply valves AV2-1 toAV2-3, and the ozone inlet valves AV1-2, AV1-3 are closed, then theozone inlet valve AV1-1 is opened, and the ozone gas is reserved intothe buffer tank 102-1 while adjusting the flow rate by the first massflow controller 241 a-1 (ozone filing step (step 3 a-1)).

When a prescribed amount of ozone gas is reserved into the buffer tank102-1 after elapse of a prescribed time, and the pressure in the buffertank 102-1 reaches. For example, 100000 Pa, as shown in [2] of FIG. 14,the ozone inlet valve AV1-1 is closed and the ozone supply valve AV2-1is opened, and the ozone gas reserved into the buffer tank 102-1 issupplied into the processing chamber 201 (ozone supplying step (step 3b-1)). In the ozone supplying step (step 3 b-1), the ozone gas reservedinto the buffer tank 102-1 is supplied (flush-supplied) into theprocessing chamber 201 pulsatively. The ozone gas causes surfacereaction with TEMAH which is chemically adsorbed on the surface of thewafer 200, to thereby form the HfO₂ film on the wafer 200. In addition,in the ozone supplying step (step 3 b-1), the pressure in the processingchamber 201 immediately after supplying ozone is set to be, for example,in a range of 0.1 to 1000 Pa.

Also, as shown in [2] of FIG. 14, in parallel to execution of the ozonesupplying step (step 3 b-1), the ozone inlet valve AV1-2 is opened, andthe ozone gas is reserved into the buffer tank 102-2, while adjustingthe flow rate by the first mass flow controller 241 a-2 (ozone reservingstep (step 3 a-2).

When a prescribed amount of ozone gas is reserved into the buffer tank102-2 after elapse of a prescribed time, and the pressure in the buffertank 102-2 reaches, for example, 100000 Pa, as shown in [3] of FIG. 14,the ozone inlet valve AV1-2 is closed, and the ozone supply valve AV2-2is opened, and the ozone gas reserved into the buffer tank 102-2 issupplied into the processing chamber 201 (ozone supplying step (step 3b-2)). In the ozone supplying step (step 3 b-2), the ozone gas reservedinto the buffer tank 102-2 is supplied (flush-supplied) into theprocessing chamber 201 pulsatively. The ozone gas is chemically adsorbedon the surface of the wafer 200, to cause surface reaction with TEMAH,and the HfO₂ film is formed on the wafer 200. Note that in the ozonesupplying step (step 3 b-2), the pressure in the processing chamber 201immediately after supplying ozone is set, for example, within a range of0.1 to 1000 Pa.

Further, as shown in [3] of FIG. 14, in parallel to execution of theozone supplying step (step 3 b-2), the ozone inlet valve AV1-3 isopened, and the ozone gas is reserved into the buffer tank 102-3, whileadjusting the flow rate by the first mass flow controller 241 a-3 (ozonereserving step (step 3 a-3)).

When a prescribed amount of ozone gas is reserved into the buffer tank102-3 after elapse of a prescribed time, and the pressure in the buffertank 102-3 reaches, for example, 100000 Pa, as shown in [4] of FIG. 14,the ozone inlet valve AV1-3 is closed and the ozone supply valve AV2-3is opened, and the ozone gas reserved into the buffer tank 102-3 issupplied (flush-supplied) into the processing chamber 201 pulsatively.The ozone gas causes surface reaction with TEMAH which is chemicallyadsorbed on the surface of the wafer 200, to thereby form the HfO₂ filmon the wafer 200. In addition, in the ozone supplying step (step 3 b-3),the pressure in the processing chamber 201 immediately after supplyingozone is set, for example, within a range of 0.1 to 1000 Pa.

Further, as shown in [4] of FIG. 14, in parallel to execution of theozone supplying step (step 3 b-3), the ozone inlet valve AV1-1 isopened, and the ozone gas is reserved into the buffer tank 102-1, whileadjusting the flow rate of the first mass flow controller 241 a-3 (ozonereserving step (step 3 a-1)).

Thereafter, the steps from the ozone reserving step (step 3 a-1) to theozone supplying step (step 3 b-3) are set as one cycle, and afterrepeating this cycle multiple number of times, the ozone supplyingvalves AV2-1 to AV2-3 are closed, to thereby end the oxide film formingstep (step 3). In addition, during executing and after ending the oxidefilm forming step (step 3), the fifth valve 243 e of the exhaust tube231 is always opened, to thereby exhaust the inside of the processingchamber 201 by the vacuum pump 246, so that the residual ozone andintermediate body of ozone are removed from the processing chamber 201.In addition, it is also acceptable that the opening degree of the fifthvalve 243 e is adjusted and the pressure in the processing chamber 201is adjusted. Note that when N₂ being purge gas, is supplied into theprocessing chamber 201 until the removal of the residual ozone andintermediate body of ozone from the processing chamber 201 is completed,the effect of excluding the residual ozone and intermediate body ofozone from the processing chamber 201 is further increased.

(Repeating Step)

Thereafter, the steps from the source gas supplying step (step 1) to theoxide film forming step (step 3) are set as one cycle, and by repeatingthis cycle multiple number of times, the HfO₂ film of a prescribedthickness is formed on the wafer 200, and the substrate processing stepaccording to this embodiment is ended. Then, the wafer 200 afterprocessing is unloaded from the processing chamber 201, by a procedurereverse to the wafer loading step.

Note that in this embodiment, the number of supply routes of the ozonegas (the number of buffer tanks 102-1 to 102N) provided in parallel isdecided based on a balance between a processing time and a manufacturingcost required for forming the oxide film.

(3) Effect of this Embodiment

According to this embodiment, one or a plurality of effects shown beloware further exhibited, in addition to the aforementioned effects.

(a) According to this embodiment, the time interval of the pulse-supplyis narrowed by controlling the time interval for opening the ozonesupply valves AV2-1 to AV2-N, to thereby increase the speed of theoxidation processing and it becomes possible to improve the throughput(productivity) of processing substrates.(b) Further, according to this embodiment, waste of ozone dischargedfrom a vent line is reduced. Therefore, the service life of the ozonizer52 can be prolonged, and a running cost can be reduced.

Other Embodiment of the Present Invention

As described above, embodiments of the present invention arespecifically described. However, the present invention is not limited tothe aforementioned embodiments, and can be variously modified in a rangenot beyond its gist.

For example, the present invention can be applied to a case of formingfilms, such as a film other than the HfO_(x) film (Si oxide film (SiO),Hf oxide film (HfOx), Zr oxide film (ZrO), Al oxide film, Ti oxide film,Ta oxide film, Ru oxide film, and Ir oxide film).

As the source gas, it is possible to use not only the TEMAH gas obtainedby vaporizing tetrakisethylmethyl amino hafnium (TEHAH), being theliquid source which is a liquid at a room temperature, but also the gasobtained by vaporizing other organic metal liquid source such astetrakisethylmethyl amino zirconium. Also, as the oxide gas, it ispossible to use not only ozone (O₃), but also other oxygen-containinggas.

Also, as the source gas supplied into the processing chamber 201, it ispossible to use the gas, being a vapor at a room temperature, other thanthe gas obtained by vaporizing the source, being the liquid at a roomtemperature by the vaporizer 242, depending on the kind of the thin filmformed on the wafer 200. In such a case, it is also acceptable that thesource gas supply source and the mass flow controller (both of them arenot shown) are provided, instead of the liquid source supply source, theliquid mass flow controller 240, and the vaporizer 242. It is alsoacceptable that the second carrier gas supply tube 234 b is removed,depending on the kind and concentration of the oxide gas supplied intothe processing chamber 201.

Also, third and fourth embodiments show a case in which the substrateprocessing apparatus is constituted as a normal flow type verticalsubstrate processing apparatus. However, the substrate processingapparatus is not limited thereto, and may be constituted as a side flowtype vertical substrate processing apparatus. FIG. 17 is a schematicblock diagram in a case that the gas supply unit according to the thirdembodiment is applied to the side flow type vertical substrateprocessing apparatus.

Preferred Aspects of the Present Invention

Next, preferred aspects of the present invention will be additionallydescribed.

(Additional Description 1)

There is provided a substrate processing method, including the steps of:

supplying source gas into a processing chamber in which substrates areaccommodated;

removing the source gas and an intermediate body of the source gasremained in the processing chamber;

supplying ozone into the processing chamber in a sate of substantiallystopping an exhaust of an atmosphere in the processing chamber;

removing ozone and the intermediate body of the ozone remained in theprocessing chamber;

with these steps repeated multiple number of times, to therebyalternately supply the source gas and the ozone so as not to be mixedwith each other, and form an oxide film on the surface of the substrate.

Preferably, the source gas is a liquid source at a room temperature andunder an atmospheric pressure, and in the source gas supplying step, thesource gas is supplied into the processing chamber while exhausting theatmosphere in the processing chamber.

Further preferably, in the ozone supplying step, a pressure in theprocessing chamber immediately after supplying the ozone is 0.1 to 1000Pa.

Further preferably, in the ozone supplying step, the ozone is suppliedinto the processing chamber while adjusting the pressure in theprocessing chamber to an average pressure.

Further preferably, an ozone filing step for filing the ozone into a gasreservoir connected to the processing chamber is provided before theozone supplying step, and in the ozone supplying step, the ozonereserved into the gas reservoir is supplied into the processing chamber.

Further preferably, the ozone reserving step is performed simultaneouslywith the source gas supplying step and/or the source gas removing step.Namely, the ozone reserving step is performed simultaneously with thesource gas supplying step, simultaneously with the source gas removingstep, or simultaneously with the source gas supplying step and thesource gas removing step.

Further preferably, in the ozone reserving step, the ozone is reservedinto the gas reservoir, until the pressure in the gas reservoir becomes100000 Pa.

Further preferably, in each of the steps, the gas supply tube connectingthe gas reservoir and the processing chamber is heated to a secondtemperature, while heating the substrate to a first temperature andfurther while cooling the gas reservoir to a third temperature, whereinthe first temperature is set higher than the second temperature, and thesecond temperature is set higher than the third temperature.

(Additional Description 2)

There is provided the substrate processing method, including the stepsof:

supplying source gas into a processing chamber in which substrates areaccommodated;

exhausting an atmosphere in the processing chamber;

reserving ozone into a gas reservoir connected to the processingchamber;

supplying into the processing chamber the ozone reserved into the gasreservoir; and

exhausting the atmosphere in the processing chamber;

with these steps repeated multiple number of times, to therebyalternately supply the source gas and the ozone so as not to be mixedwith each other, and form an oxide film on the surface of the substrate.

(Additional Description 3)

There is provided a substrate processing method, including the steps of:

loading substrates into a processing chamber;

supplying ozone into the processing chamber, in a state of substantiallystopping exhaust of an atmosphere in the processing chamber; and

removing the ozone and an intermediate body of the ozone remained in theprocessing chamber,

with these ozone supplying step and ozone removing step repeatedmultiple number of times, to thereby form an oxide film on the surfaceof the substrate.

Preferably, in the ozone supplying step, the pressure in the processingchamber immediately after supplying the ozone is 0.1 to 1000 Pa.

Further preferably, in the ozone supplying step, the ozone is suppliedinto the processing chamber while adjusting the pressure in theprocessing chamber to an average pressure.

Further preferably, the ozone reserving step for reserving the ozoneinto a gas reservoir connected to the processing chamber is providedbefore the ozone supplying step, and in the ozone supplying step, theozone reserved into the gas reservoir is supplied into the processingchamber.

Further preferably, in the ozone reserving step, the ozone if reservedinto the gas reservoir, until the pressure in the gas reservoir becomes100000 Pa.

Further preferably, in each of the steps, the gas supply tube connectingthe gas reservoir and the processing chamber is heated to a secondtemperature while heating the substrate to a first temperature andfurther while cooling the gas reservoir to a third temperature, whereinthe first temperature is set higher than the second temperature, and thesecond temperature is set higher than the third temperature.

(Additional Description 4)

There is provided a substrate processing method, including the steps of:

reserving ozone into a gas reservoir connected to a processing chamberin which substrates are accommodated;

supplying into the processing chamber the ozone reserved into the gasreservoir; and

exhausting an atmosphere in the processing chamber;

with these steps repeated multiple number of times, to thereby form anoxide film on the surface of the substrate.

(Additional Description 5)

There is provided a substrate processing apparatus, including:

a processing chamber processing a substrate;

a gas supply unit supplying ozone into the processing chamber;

an exhaust unit exhausting an atmosphere in the processing chamber; and

a controller,

with the gas supply unit including an ozone supply path connected to theprocessing chamber, and an ozone supply valve performing open/close ofthe ozone supply path.

with the exhaust unit including an exhaust path connected to theprocessing chamber, and an exhaust valve for opening and closing theexhaust path,

with the controller controlling the gas supply unit and the exhaust unitso that the ozone is supplied into the processing chamber from the ozonesupply path in a state of substantially stopping an exhaust of theatmosphere inside of the processing chamber, when the ozone is suppliedinto the processing chamber.

Preferably, the gas supply unit is disposed on the upper stream side ofthe ozone supply valve and has a gas reservoir for accumulating ozone,and the controller controls the gas supply unit so as to supply theozone accumulated in the gas reservoir into the processing chamber byopening the ozone supply valve, after the ozone is supplied into theozone supply path and the ozone is accumulated in the gas reservoir.

Further preferably, a volume ratio of the gas reservoir to a volume ofthe processing chamber is 1/2100 to 1/105.

Further preferably, the gas supply unit includes a cooling unit having acooling medium that cools the gas reservoir.

Further preferably, an inner wall of the gas reservoir is coated withany one of a Fe oxide film, a Ti oxide film, an Al oxide film, a Nioxide film, and a Cr oxide film.

(Additional Description 6)

There is provided a substrate processing apparatus, including:

a processing chamber that accommodates a substrate;

a heating unit disposed outside the processing chamber, for heating anatmosphere and the substrate in the processing chamber;

a gas supply unit that supplies a prescribed gas to the processingchamber;

an exhaust unit that exhausts the atmosphere in the processing chamber;and

a controller that controls at least gas supply operation in the gassupply unit or gas exhaust operation in the exhaust unit,

with the gas supply unit having an ozone supply part for supplying ozoneinto the processing chamber,

with the ozone supply part having an ozone supply path, a gas reservoirfor accumulating ozone, disposed on the ozone supply path on an upperstream side of a connection part of the ozone supply path and theprocessing chamber, and an ozone supply valve for opening and closingthe ozone supply path, disposed on the ozone supply path, being theconnection part between the gas reservoir and the processing chamber,

wherein the controller controls the gas supply unit in such manner that,when ozone is supplied into the processing chamber, first, the ozonesupply valve is closed, then ozone is flown to the ozone supply path,and a prescribed amount of ozone is accumulated in the gas reservoir,then the ozone supply valve is opened and ozone accumulated in the gasreservoir is supplied to the processing chamber, to thereby form adesired oxide film on the substrate. The pressure in the processingchamber is more reduced than an atmospheric pressure, and an ozonesupply accumulating pressure is higher than the pressure in theprocessing chamber, and substrates are horizontally disposed in theprocessing chamber in multiple stages. In this state, when the ozonesupply valve is opened, ozone is supplied along an upper surface of eachsubstrate pulsatively, and the substrate is processed uniformly in thesurface by ozone.

Preferably, there is provided the substrate processing apparatus,wherein the controller controls the gas supply unit, so that a firststep of flowing the ozone to the ozone supply path and accumulating aprescribed amount of the ozone in the gas reservoir, and a second stepof opening the ozone supply valve and supplying into the processingchamber the ozone accumulated in the gas reservoir are repeatedprescribed number of times, when the ozone is supplied into theprocessing the chamber, to thereby form a desired oxide film on thesubstrate. Thus, ozone is continuously supplied to the substratepulsatively. As a result, the substrate is processed uniformly in thesurface.

Further preferably, there is provided the substrate processingapparatus, wherein the exhaust unit has an exhaust path; a vacuumexhaust part connected through the exhaust path; and an exhaust valvefor opening/closing the exhaust path, with the controller controllingthe gas supply unit and the exhaust unit so that the ozone accumulatedin the gas reservoir is supplied into the processing chamber from thegas reservoir in a state of stopping exhaust of the processing chamberor extremely squeezing the exhaust of the processing chamber, to therebyform a desired oxide film on the substrate. When the exhaust is stoppedor squeezed at the time of oxidizing the substrate by ozone, thesubstrate is processed uniformly in the surface.

Further preferably, there is provided the substrate processingapparatus, wherein the pressure in the processing chamber immediatelyafter supplying the ozone is set to be 0.1 to 1000 Pa. In a case of thepressure of under 0.1 Pa, uniformity in the surface of the oxide film islowered, and when the pressure exceeds 1000 Pa, the thickness of theoxide film does not become uniform in the surface. Accordingly, when theoxide film is formed, the pressure in the processing chamber immediatelyafter supplying ozone is set to be 0.1 to 1000 Pa.

Further preferably, there is provided the substrate processingapparatus, wherein the ozone is accumulated in the gas reservoir, untilthe pressure in the gas reservoir reaches 100000 Pa. When the pressureof the gas reservoir is set to the aforementioned pressure, uniformoxidation and film-formation in the surface of the substrate is possibleby ozone supplied to the substrate pulsatively, when the ozone supplyvalve is opened.

Further preferably, there is provided the substrate processingapparatus, wherein a volume ratio of the gas reservoir to a volume ofthe processing chamber is 1/2100 to 1/105. Thus, by deciding the volumeratio, the wafer can be uniformly oxidized in the surface and uniformfilm-formation in the surface is possible.

Further preferably, there is provided the substrate processingapparatus, wherein the controller controls the gas supply unit and theexhaust unit so as to adjust the pressure in the processing chamber toan average pressure when the ozone is supplied into the processingchamber, to thereby form a desired oxide film. Here, the averagepressure is the pressure obtained from the pressure for supplying ozonewithout closing the exhaust valve. When the pressure in the processingchamber is set to be the average pressure, a desired oxide film can beformed uniformly in the surface of the substrate.

Further preferably, there is provided the substrate processingapparatus, wherein the exhaust unit is connected to a lower part of theprocessing chamber. When the exhaust unit is provided in the lower part,source gas (processing gas) can be exhausted after flowing through theprocessing chamber, and therefore there is no waste of source gas(processing gas). Moreover, the exhaust unit in the lower part issuitable for forming the flow suitable for oxidation and film-formationwithout disturbing the flow of the gas in the processing chamber.

Further preferably, there is provided the substrate processingapparatus, wherein the processing chamber includes an outer tube and aninner tube set inside of the outer tube, with at least its lower endopened, in which the plurality of substrates are laminated andaccommodated, and the gas supply unit has a plurality of gas supplynozzles having gas jet holes erected inside of the inner tube so as tobe extended in a laminating direction of the plurality of substrates,and further the processing chamber has a plurality of exhaust portsprovided in the inner tube, at positions opposed to the gas supplynozzles.

When the processing chamber is thus constructed, a horizontal flow canbe formed on each substrate, and therefore in-surface uniformity of eachsubstrate can be improved. Moreover, both of the processing gas afterpassing through a gap between the inner tube and the outer tube, and theprocessing gas from an open end of the inner tube can be exhausted.Therefore, substitution efficiency of the gas can be improved.

Further preferably, there is provided the substrate processingapparatus, wherein the ozone supply part includes a cooling unit havinga cooling medium for cooling the gas reservoir.

When this gas reservoir is cooled, the service life of ozone isprolonged, and therefore the substrate can be processed in a state of aconstant quality.

Further preferably, there is provided the substrate processingapparatus, wherein the cooling medium is either one of the cooling waterand a peltier element. With a simple structure, accumulation of thesupplied ozone can be surely cooled, and therefore reliability isimproved.

Further preferably, there is provided the substrate processingapparatus, wherein an inner wall of the gas reservoir is coated with anyone of a Fe oxide film, a Ti oxide film, an Al oxide film, a Ni oxidefilm, and a Cr oxide film. Thus, reaction between ozone and cooledreservoir is prevented, and therefore reliability of processingsubstrates can be improved.

Further preferably, there is provided the substrate processingapparatus, wherein the gas supply unit has a source gas supply part thatsupplies source gas different from ozone into the processing chamber,and the source gas supply part has a source gas supply path and a sourcegas supply valve disposed in the source gas supply path, for opening andclosing the source gas supply path, and the controller controls the gassupply unit and the exhaust unit so that the source gas and the ozoneare alternately repeatedly supplied into the processing chamber multiplenumber of times so as not to be mixed with each other, and when thesource gas is supplied into the processing chamber, the source gas issupplied into the processing chamber from the source gas supply path,and in a state of closing the ozone supply valve, the ozone is flown tothsand a prescribed amount of the ozone is accumulated in the gasreservoir, to thereby form a desired oxide film on the substrate.

With this structure, ozone can be accumulated in the gas reservoir whileprocessing the substrate by the source gas. Ozone is supplied to thesubstrate by opening the ozone supply valve, immediately after endingthe processing by the source gas, and the ozone causes reaction with rawmaterials of the source gas, to thereby oxidize the substrate or form afilm thereon.

Further preferably, there is provided the substrate processingapparatus, wherein the oxide film is any one of the Si oxide film, Hfoxide film, Zr oxide film, Al oxide film, Ti oxide film, Ta oxide film,Ru oxide film, and Ir oxide film.

Further preferably, the source gas is any one of an organic compoundcontaining Si atom, Hf atom, Zr atom, Al atom, Ti atom, Ta atom, Ruatom, and Ir atom or chloride of the aforementioned atoms.

Further preferably, there is provided the substrate processingapparatus, wherein the controller further controls the gas supply unitand the exhaust unit so that the remained source gas or ozone isremoved, after supply of the source gas into the processing chamber isstopped and after supply of the ozone into the processing chamber isstopped.

Thus, the processing chamber is cleaned.

(Additional Description 7)

There is provided a manufacturing method of a semiconductor device,including:

a first step of reserving ozone into a gas reservoir connected to aprocessing chamber;

a second step of supplying into the processing chamber ozone reservedinto the gas reservoir; and

a third step of exhausting an atmosphere in the processing chamber,

with the steps from the first step to the third step repeatedlyperformed one or more times, to thereby form an oxide film of aprescribed thickness on the surface of a plurality of substrateslaminated and accommodated in the processing chamber.

By these steps, the substrate can be processed uniformly in the surfaceand the oxide film can be formed.

Preferably, there is provided the manufacturing method of thesemiconductor device, wherein when the steps from the first step to thethird step are repeated, at least one or more first step and third stepare simultaneously performed. When ozone is exhausted while beingsupplied pulsatively, the oxide film can be uniformly formed in thesurface.

(Additional Description 8)

There is provided the manufacturing method of the semiconductor devicefor forming the oxide film of a prescribed thickness on the surface of aplurality of substrates laminated and accommodated in a processingchamber by supplying source gas and ozone into the processing chamberalternately and repeatedly prescribed number of times so as not to bemixed with each other, including:

a first step of supplying the source gas into the processing chamber;

a second step of reserving the ozone into a gas reservoir connected tothe processing chamber;

a third step of supplying into the processing chamber ozone reservedinto the gas reservoir; and

a fourth step of exhausting an atmosphere in the processing chamber,

with the steps from the first step to the fourth step repeated at leastone or more times, to thereby form an oxide film of a prescribedthickness on the surface of a plurality of substrates laminated andaccommodated in the processing chamber. When these steps are executed, adesired film can be uniformly formed in the surface of the substrate.

Preferably, there is provided the manufacturing method of thesemiconductor device, wherein when the steps from the first step to thefourth step are repeated, at least one or more first step and secondstep are simultaneously performed. With this structure, ozone can beaccumulated in the gas reservoir while processing the substrates by thesource gas. Ozone is supplied to the substrate, by opening the ozonesupply valve immediately after processing by the source gas is ended,and the ozone causes reaction with raw materials of the source gas, tothereby perform oxidation and film-formation.

What is claimed is:
 1. A method of manufacturing a semiconductor device,comprising: forming an oxide film on a surface of a substrate byalternately supplying a source gas and an ozone gas so as not to bemixed with each other by setting (a)-(e) as one cycle and repeating thecycle multiple times: (a) supplying the source gas into a processingchamber in which the substrate is accommodated; (b) first-exhausting anatmosphere in the processing chamber; (c) reserving the ozone gas into agas reservoir connected to the processing chamber, with a volume ratioof 1/2100 to 1/105 to the processing chamber, by supplying the ozone gasinto the gas reservoir; (d) flush-supplying the ozone gas reserved inthe gas reservoir into the processing chamber in a state ofsubstantially stopping exhaust of an atmosphere in the processingchamber while maintaining the supply of the ozone gas into the gasreservoir and so that the within a range of 0.1 to 1000 Pa, after aprescribed amount of the ozone gas is reserved in the gas reservoir; and(e) second-exhausting an atmosphere in the processing chamber.
 2. Themethod of manufacturing a semiconductor device according to claim 1,wherein at least a part of the first-exhaust and the reserve of theozone gas are performed simultaneously.
 3. The method of manufacturing asemiconductor device according to claim 1, wherein in the supply of theozone gas, the substrate is heated at a temperature of the substrate of180° C. to 250° C. and a temperature in the gas reservoir is set to thetemperature of the substrate or less.
 4. The method of manufacturing asemiconductor device according to claim 3, wherein in the supply of theozone gas, the substrate is heated at the temperature of the substrateof 180° C. to 250° C., a temperature of an ozone gas supply path is setto the temperature of the substrate or less, and the temperature in thegas reservoir is set to the temperature of the ozone supply path orless.
 5. The method of manufacturing a semiconductor device according toclaim 1, wherein an inside of the gas reservoir is cooled.
 6. The methodof manufacturing a semiconductor device according to claim 1, wherein aninner wall of the gas reservoir is coated with a film.
 7. The method ofmanufacturing a semiconductor device according to claim 6, wherein thefilm is an oxide film.
 8. A method of manufacturing a semiconductordevice, comprising: forming an oxide film on a surface of a substrate bysetting (a)-(c) as one cycle and repeating the cycle multiple times: (a)reserving an ozone gas into a gas reservoir connected to the processingchamber, with a volume ratio of 1/2100 to 1/105 to the processingchamber, by supplying the ozone into the gas reservoir; (b)flush-supplying the ozone gas reserved in the gas reservoir into theprocessing chamber in a state of substantially stopping exhaust of anatmosphere in the processing chamber while maintaining the supply of theozone gas into the gas reservoir, after a prescribed amount of the ozonegas is reserved in the gas reservoir and so that the pressure in theprocessing chamber immediately after supplying the ozone gas is set tobe within a range of 0.1 to 1000 Pa; and (c) exhausting an atmosphere inthe processing chamber.
 9. The method of manufacturing a semiconductordevice according to claim 8, wherein in the supply of the ozone gas, thesubstrate is heated at a temperature of the substrate of 180° C. to 250°C. and a temperature in the gas reservoir is set to the temperature ofthe substrate or less.
 10. The method of manufacturing a semiconductordevice according to claim 9, wherein in the supply of the ozone gas, thesubstrate is heated at the temperature of the substrate of 180° C. to250° C., a temperature of an ozone gas supply path is set to thetemperature of the substrate or less, and the temperature in the gasreservoir is set to the temperature of the ozone gas supply path orless.
 11. The method of manufacturing a semiconductor device accordingto claim 8, wherein an inside of the gas reservoir is cooled.
 12. Themethod of manufacturing a semiconductor device according to claim 8,wherein an inner wall of the gas reservoir is coated with a film. 13.The method of manufacturing a semiconductor device according to claim12, wherein the film is an oxide film.
 14. A method of manufacturing asemiconductor device, comprising: setting (a)-(d) as one cycle andrepeating the cycle several times: (a) supplying a source gas into aprocessing chamber, by opening a first valve provided in a source gassupply path for supplying the source gas into the processing chamber inwhich a substrate is accommodated; (b) reserving an ozone gas in a gasreservoir with a volume ratio of 1/2100 to 1/105 to the processingchamber, provided in an ozone gas supply path for supplying the ozonegas into the processing chamber by opening a third valve provided at anupstream side of the gas reservoir in the ozone gas supply path with asecond valve provided at a downstream side of the gas reservoir in theozone gas supply path closed and with a fourth valve provided in anexhaust path for exhausting the atmosphere in the processing chamberopened; (c) flush-supplying the ozone gas reserved in the gas reservoirinto the processing chamber by opening the second valve with the thirdvalve opened and the fourth valve closed; and (d) exhausting anatmosphere in the processing chamber.
 15. The method of manufacturing asemiconductor device according to claim 14, wherein in the supply of theozone gas, the substrate is heated at a temperature of the substrate of180° C. to 250° C. and a temperature in the gas reservoir is set to thetemperature of the substrate or less.
 16. The method of manufacturing asemiconductor device according to claim 15, wherein in the supply of theozone gas, the substrate is heated at the temperature of the substrateof 180° C. to 250° C., a temperature of an ozone gas supply path is setto the temperature of the substrate or less, and the temperature in thegas reservoir is set to the temperature of the ozone supply path orless.
 17. The method of manufacturing a semiconductor device accordingto claim 14, wherein an inside of the gas reservoir is cooled.
 18. Themethod of manufacturing a semiconductor device according to claim 14,wherein an inner wall of the gas reservoir is coated with a film. 19.The method of manufacturing a semiconductor device according to claim18, wherein the film is an oxide film.